Class 8

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

by

Punjab State Board PSEB 8th Class Social Science Book Solutions Geography Chapter 2 Natural Resources Textbook Exercise Questions and Answers.

PSEB Solutions for Class 8 Social Science Geography Chapter 2 Natural Resources

SST Guide for Class 8 PSEB Natural Resources Textbook Questions and Answers

I. Answer the following questions in 1-15 words:

Question 1.
Into which relief features can the land be divided?
Answer:
Mountains, plateaus, and plains.

Question 2.
What is the importance of plains?
Answer:
Plains support agriculture and dense population. These meet human needs. Plains are suitable for the development of vegetation and crops.

Question 3.
What are the factors that affect the formation of soils?
Answer:
Parent rocks, climate, plants and animals.

Question 4.
How many types of soils are found in India? Write the names of these types.
Answer:

  • Alluvial soils
  • Black soils
  • Red soils
  • Laterite soils
  • Forest and Mountain soils
  • Desert soils.

Question 5.
What type of crops can be grown on Black soil?
Answer:
Cotton, wheat, jowar, flax, tobacco, sun flower, crops are grown in Black soils. Rice and sugarcane are grown with the help of irrigation.

Question 6.
Write the names of main sources of water.
Answer:

  1. Rainfall
  2. Rivers and streams
  3. Canals
  4. Tanks
  5. Groundwater.

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 7.
What is given by the natural vegetation to man?
Answer:

  1. Timber (wood) which is used for buildings.
  2. Fruit, medicines and other products.

Question 8.
Name the types of forests found in India.
Answer:

  1. Evergreen forests
  2. Deciduous forests
  3. Desert forests
  4. Mountain forests
  5. Delta forests.

Question 9.
What are migratory birds and where do they come from?
Answer:
In cold season birds migrate to India. These are called migratory birds. These come from Mosay Siberia and China.

II. Answer the following questions in 50-60 words :

Question 1.
Write about the land use in India.
Answer:
Land use pattern. India has a total geographical area of 32.8 crore hectares. Main characteristics of land use are given below:

  1. Net Sown Area. About 46% of total land (77 crore hectares) is net sown area. This vast area shows the importance of agriculture in India as crops are grown in it
  2. Fallow land. About 8% land (2.2 crore hectares) is left as fallow land and is cultivated after two or three years.
  3. Forests. About 22.2% of land is (6.6 crore hectares) under forests. It should be 33%. Afforestation be done and’ deforestation be banned.
  4. Plantation crops. About 1% land is under plantation crops like tea, coffee, etc.
  5. Other uses. Land under permanent grassland, cultivable waste and not available for cultivation amounts to about 5 crore hectares.
  6. Area under forests is increasing. Fallow land has been reduced in area. Net sown area under doubled cropped area is also increasing.

Question 2.
After mentioning the types of soil write the importance of alluvial soil.
Answer:
There are six types of soils in India :

  1. Alluvial soils
  2. Black soils
  3. Red soils
  4. Laterite soils
  5. Forest and Mountain soils
  6. Desert soils.

Alluvial Soils: These are made up of fine particles. These are clay soils and fertile soils. Therefore, the alluvial plains are very useful for agriculture. For example, the Indus- Ganga-Brahmputra plain of India. It has two types-Khadar and Bangar soils.

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 3.
How is the soil resource being conserved?
Answer:
Soil Conservation. Soil is a very fundamental natural resource. Soil formation is a slow process, but it is easily lost by soil erosion. Sound farming practices and measures be adopted to conserve, protect, renew and maintain soil fertility.

These methods constitute soil conservation.

  • Afforestation: Afforestation and reforestation is needed to hold the soil.
  • Controlled grazing: The number of cattle to be grazed on slopes should be according to the carrying capacity of the pastures.
  • Terraced agriculture: Slopes must be cut into a series of terraces (fields) for cultivation so as to slow down the flow of rain water.
  • River dams: River dams are built in the upper course of rivers to control floods and check soil erosion.
  • Crop rotation: Crop rotation system be applied and the land should be allowed fallow for some time. Soil fertility can be maintained in this way.

Question 4.
Give the importance of rivers and canals.
Answer:
India has a total of 1869 billion cubic metre water resources. Out of this, only 660 billion cubic metres have been utilized for irrigation. India needs to plan these water resources to be utilized for agriculture. For this more multipurpose projects should be planned and completed. Ground water resource should be used for providing water power to tubewells. A lot has been done to manage our water resources, but due to technological and financial limitations, still much of water goes waste to oceans.

Question 5.
How the water can be conserved?
Answer:
Water is a vital resource for the development of economic activities. Water should be conserved in the following ways. Waters of ocean, river and lakes should not be polluted. It should he saved from urban waste and chemicals of industries. It should be recycled to use it again. Dams should be built across the rivers and lakes to store water in reservoirs.

Question 6.
Write a note on Deciduous forests.
Answer:
Deciduous forests shed their leaves in a specific season. In spring season, these leaves become green.’These are the most widespread forests in India. These are economically very important from the point of getting timber. These include Sal, Teak, Bamboo, Shisham and Khair trees.

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 7.
What steps have been taken by Govt, of India for protection and conservation of wildlife? (P.S.E.B. 2020)
Answer:
Wildlife plays an important role in the human progress and civilisation. The primitive man had to depend on animals for food and other basic needs. Later on, man began to domesticate animals. Still hunting is carried on in many parts of the world. Many useful and valuable species are becoming extinct due to hunting or killing of animals. Man has upset the ecological balance by killing of birds and animals.

Many steps have been taken for the preservation of wildlife.

  • Parks and sanctuaries have been established in hilly areas and forests.
  • Hunting of some rare species of animals has been banned.
  • Public attention is focused on making efforts for the preservation of wildlife.
  • Wild animals like lion, tiger, deer, etc. are protected during closed season when they cannot be hunted.

III. Answer the following questions in about 125-130 words :

Question 1.
What are Natural Resources? Write down the types and importance of soils and natural vegetation.
Answer:
Natural Resources are free gifts provided by nature. These include land, water, soil, forests, wildlife, minerals, etc.
1. Soils: The main types of soils are :

  • Alluvial soils
  • Black soils
  • Red soils
  • Laterite soils
  • Forests and Mountain soils
  • Desert soils.

Importance: Soil is a valuable resource. It is required for cultivation of crops. Fertile soil is the basis of developed agriculture. It becomes more important for a country like India which is an agricultural country. Many types of soils are found in India and many types of crops are grown on it.

2. Vegetation: The following types of vegetation is found in India :

  • Evergreen forests
  • Deciduous forests
  • Desert forests
  • Mountain forests .
  • Delta forests.

Importance of Forests: Forests are a valuable resource like a river system, it is a multiple resource. Forests provide mankind with a number of products. Forests have greatly influenced human activities. Modem civilization depends more and more on forests.

Following are the direct and indirect advantages of forests :

  • Forests provide many things to meet our food requirements like wild fruits, nuts, berries, etc. Many tribes are dependent on gathering of these products in forests.
  • Forests are a source of timber for house-building, furniture-making, ship-building, etc.
  • Forests supply about 40% of fuel of the world. Wood has been the major source of fuel in house smelting industries and running locomotives.
  • Soft wood trees supply raw materials, wood pulp, paper, rayon industries.
  • Many products like rubber, pitch, gum, tanning materials, cork, camphor, fir, herbs, etc. are gathered from forests.
  • Forests provide plywood and fibre wood for packing purposes

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 2.
How the water and wildlife can be conserved? Express your views.
Answer:
India is rich in fauna and flora. There is a great biological diversity in, India. There are about 90000 known species of animals. It has 2500 species of fish and 1200 species of birds. But many of these fauna have been destroyed by-man. Many rare species have become extinct in India. Our rich wildlife is rich heritage formed through centuries. It must be preserved. Many of the fauna are found only in India such as swamp deer, the one-horned rhinoceros, the bison, Kashmir stag, Nilgai, etc. These rare species are in danger of extinction.

The following measures have been taken for conserving and protecting wildlife as well as its bio diversity in the country. Wildlife is a gift of nature and a thing of beauty. Wildlife Act provides for the protection and conservation of these species.

For this purpose :

  • A network of 89 national parks, 490 sanctuaries and 13 biosphere reserves have been established.
  • Under Project Tiger 27 Tiger Projects in 14 states have been set up.
  • 15 mangroves have already been identified for intensive conservation and management purpose.

Conservation and Management of Water Resources
1. Watershed Management. The management of the divide between two drainage basin called watershed is taken as a physiographic unit. The inter-basin management of water helps to divert water from surplus areas to scarcity areas. It also helps replenish ground water resources. It involves integrated development of two or diverse basins and saves on technical and financial resources.

2. Rainwater Harvesting. Rainwater is stored in roof top tanks, on ground Or underground tanks or check dams, percolation pits, etc. during rainy season and then it is used for irrigation, improving vegetation cover in dry season. While it increases productivity it also replenishes ground water resources.

IV. Map Skill

Question 1.
Show the following on the outline map of India :
1. Northern plains of India
2. Ganga and Brahmputra Rivers
3. Region of Alluvial soils
4. A state with black soil
5. An area of evergreen forests
6. A region with mountain and delta vegetation.
Answer:
PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources 1

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

V. Activity

Question 1.
Show eight types of soils on the map of India.
Answer:
PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources 2

PSEB 8th Class Social Science Guide Natural Resources Important Questions and Answers

Multiple Choice Questions :

Question 1.
Which one of the following is not a type of forest found in India?
(a) Evergreen forest
(b) Tidal forest
(c) Deciduous forest
(d) Desert forest.
Answer:
(b) Tidal forest.

Question 2.
Cutting down of trees is called :
(a) Afforestation
(b) Deforestation
(c) Slash and Burn
(d) Strip cropping
Answer:
(b) Deforestation.

Question 3.
Sunderbans is the habitat of :
(a) Tiger
(b) Lions
(c) Elephants
(d) Camels
Answer:
(a) Tiger.

Question 4.
Which is the oldest landmass of India?
(a) Northern Plain
(b) Peninsular Plateau
(c) Himalayas
(d) Aravallis.
Answer:
(b) Peninsular Plateau.

Question 5.
Natural vegetation and wildlife is found in :
(a) Biosphere
(b) Hydrosphere
(c) Atmosphere
(d) None of the above.
Answer:
(a) Biosphere.

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 6.
Following picture shows a specific type of forests, names these forests.
PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources 3
(a) Evergreen forests
(b) Tidal forests
(c) Deciduous forests
(d) Deserts
Answer:
(a) Evergreen forests.

Question 7.
Study the following picture and give the answer what this picture is explained?
PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources 4
(a) Afforestation
(b) Deforestation
(c) Slash and Burn
(d) Strip Gopping
Answer:
(b) Deforestation.

Question 8.
Jhoolan Devi does the agricultural work with her family but her family is forced to migrate to other place to do agriculture due to reduction in soil fertility. What type of farming does this situation represent?
(a) Permanent agriculture
(b) Horticulture.
(c) Intensive agriculture
(d) Jhum cultivation.
Answer:
(d) Jhum cultivation.

Question 9.
How much part of total area of India is under forests? (P.S.E.B. 2020)
(a) 11.9%
(b) 52.2%
(c) 22.2%
(d) 32.2%.
Answer:
(c) 22.2%

Fill in the Blanks :

Question 1.
In India soils are of types.
Answer:
six

Question 2.
__________ is the upper most layer of the earth crust .
Answer:
soil

Question 3.
Land use depends on __________ factor.
Answer:
physical

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 4.
Ice-sheets are found in __________
Answer:
greenland

Question 5.
About ________% of the total surface area of the earth is under water.
Answer:
71

True/False :

Question 1.
The original rock called Parent Rock.
Answer:
True

Question 2.
Pollution means contamination of natural resources.
Answer:
True

Question 3.
A dripping tap wastes 100 litres in a year.
Answer:
False

Question 4.
An average urban Indian uses about 35 litres of water everyday.
Answer:
False

Question 5.
Land suitable for agriculture is called Arabic land.
Answer:
True.

Very Short Answer Type Questions

Question 1.
Describe the distribution of Land and Water on earth.
Answer:
29%-Land and 71%-Water.

Question 2.
Why is there need for Afforestation in India?
Answer:
There should be at least 33% area under forests in India. But only 22.2% area is under forests in India. So there is need for growing trees on large scale.

Question 3.
What do you mean by culturable waste?
Answer:
Some land is culturable, but it is not cultivated due to some reasons. Such as scarcity of water, soil erosion, waterlogging, etc.

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 4.
In which areas forest and mountain soils are found? State any two characteristics.
Answer:
These soils are found along forests and hill slopes.

Characteristics:

  • These have organic elements.
  • These lack in Potash, Phosphorus, Lime. Therefore, use of fertilizer is essential.

Question 5.
What are alluvial soils?
Answer:
Alluvial soils are formed by deposition of fine sediments. These sediments are brought by the river. Sea waves also deposit these along coasts. Alluvial soils are very fertile.

Question 6.
Why is black soil called cotton soils? Name one other name of it.
Answer:
Black soil is suitable for the cultivation of cotton. So it is called cotton soil. It is also called Regur soil.

Question 7.
Where are desert soils found in India?
Answer:
Desert soils are found in Rajasthan, Punjab, Haryana and in some parts of Gujarat.

Question 8.
Why is earth called a ‘watery planet’?
Answer:
Most of the earth (71%) is covered with water. So it is called watery planet due to excess of water.

Question 9.
In which form most of water is found on earth? How much per cent is it of total water?
Answer:
Most of water is found in the form of oceans, seas and salt lakes. It contains 97.20% of total water.

Question 10.
For which purpose, most of water is used and how much?
Answer:
93.37% of total water is used for agricultural purposes.

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 11.
Where are Tanks found?
Answer:
Tanks are found in areas where there are no perennial rivers and canals. Ground water is very deep. In India most of tanks are found in southern India.

Question 12.
Write briefly about desert vegetation.
Answer:
Desert vegetation is found in arid areas. The vegetation is scanty. It includes Date palm, Cactus and Thorny bush. In India, this type of vegetation is found in Rajasthan, Gujarat and Haryana.

Question 13.
Name four trees of mountain vegetation.
Answer:

  1. Fir
  2. Deodar
  3. Oak
  4. Nuts.

Question 14.
What is terrace farming?
Answer:
Terrace farming. The growing of crops on level steps or terraces that have been constructed on hillsides.

Question 15.
What is a wildlife sanctuary?
Answer:
A wildlife sanctuary is dedicated to protect wildlife and conserve forests.

Question 16.
What are Protected forests?
Answer:
There are forests reserved for timber but grazing is allowed subject to minor restrictions. These are 29.2% of total forests.

Question 17.
What is contour ploughing?
Answer:
Contour Ploughing: Technique of ploughing parallel to the contours of a hill slope rather than up and down the slope, so as to reduce soil erosion.

Question 18.
What is strip cropping?
Answer:
Strip Cropping. Growing of different crops on parallel narrow strips of ground, usually following the contour patterns.

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 19.
What is a shelterbelt?
Answer:
Shelter belt: In dry regions, rows of trees are planted to check the wind movement for protecting soil cover.

Short Answer Type Questions

Question 1.
Write a note on alluvial soils. Classify these into two groups.
Answer:
Alluvial soils. These cover 45% land of India :

  1. Alluvial soil is deposited by rivers.
  2. These soils are limited to river basins and plains.
  3. These are very fertile soils.
  4. These consist of fine-grained. clay and sand.
  5. These soils are rich in potash, but poor in phosphorus.
  6. These are usually deep soils.

Types:
(a) Khadar soils
(b) Bangar soils.

(a) Khadar soils are new alluvial soils while
(b) Bangar soils are old alluvial soils.

Question 2.
State the characteristics of Black soils. Describe its distribution in India.
Answer:
Black Soils. Black soils are mainly found over the Deccan Lava tract (Deccan trap) including Maharashtra, Madhya Pradesh, Gujarat and Andhra Pradesh. These soils are found in river valleys of Narmada, Tapti, Godavari and Krishna. These soils have

been formed due to weathering of lava rocks. These soils cover an area of about 5 lakh sq. km. These soils are rich in lime, iron, magnesia and alumina. But these lack in phosphorus, nitrogen and organic matter. These are also called ‘Regur Soils’. These soils are most suitable for cotton cultivation and are known as ‘Black Cotton Soils’. These soils are compared with Chernozem soils of Russia and Prairies soils of U.S.A. These soils can hold water. These soils are suitable for rice, wheat, jawar, sugarcane, tobacco and oilseeds.

Question 3.
Write a note on desert soils.
Answer:
Desert Soils. These soils cover 2 lakh sq. km. area in dry areas of Rajasthan, Gujarat, Punjab, Haryana. These coarse soils are suitable for the cultivation of jawar, bajra, cotton, oats, maize, pulses etc. Methods of irrigation are used. These are sandy soils and are infertile. These do not hold water. So these are used for dry crops. In India 4.3% area is covered by desert soils.

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 4.
State the characteristics and distribution of Red Soils in India.
Answer:
Red Soils: These soils are found in Chotta Nagpur plateau, Telangana, Nilgiris, Tamil Nadu, Karnataka, Andhra Pradesh and areas on periphery of Deccan Plateau. These soils have been formed due to decomposition of underlying igneous rocks under heavy rainfall. These soils have different shades of red and yellow. The red colour of these soils is due to oxidation and diffusion of iron in hard crystalline rocks. These are used for the cultivation of millets, pulses, linseed, tobacco, etc. These soils cover the largest area (10.6%) in Peninsular India, particularly S.E. part of the Peninsula. These soils are poor in lime, nitrogen and humus. Fertilizers are added to make these fertile.
PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources 5

Question 5.
What are the characteristics of laterite soils? Describe its distribution in India.
Answer:

  • The laterite soils are of brick colour.
  • These are shallow, acidic and less fertile.
  • These are less fertile due to leaching of soil.
  • These are poor in nitrogen, potash but very rich in iron.
  • These are found in Tamil Nadu, Western Ghats, Rajmahal hills, Vindhyas, Satpuras and Malwa plateau. These soils cover 7.5% area of the country
  • Some areas of Maharashtra, Andhra Pradesh, Orissa, Karnataka, Jharkhand also have laterite soils.
  • These are suitable for cultivation of Rubber, Tea, Coffee and Coconut.

Question 6.
What do you mean by wildlife? Describe in brief the wildlife of India.
Answer:
Like diverse flora, our fauna is found to be equally rich and varied. There are about 80,000 known species. The country in its fresh and marine waters has as many as 2500 species of fish. Likewise there are about 1200 species of birds. In addition there are amphibians, reptiles, mammals and small insects and worms. Migratory birds also come to India during winter

Mammals: Among the mammals, the elephant is the stately animal. It is a typical animal of hot wet equatorial forests. It is found in the jungles of Assam, Kerala and Karnataka. In these areas, it rains heavily and the forests are very dense. On the other hand camels and wild asses are found in hot deserts. Camels are found in Thar desert.

Question 7.
Why is the Land considered an important resource?
Answer:
Land is considered as an important resource because:

  1. It is used for different purposes like agriculture, forests, pastures.
  2. Human beings make their houses and live on it and also it provides most of the products they need; like food, wood etc.

Question 8.
Name the five factors controlling soil formation.
Answer:
The five factors controlling soil formation are:

  1. Nature of the parent rock
  2. Topography
  3. Climate
  4. Time
  5. Organism in it.

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 9.
Write any two reasons for land degradation today.
Answer:
There are many factors which lead to the degradation of land. Both nature and human factors can lead to degradation of land.

  1. Growing population and their ever growing demand is the main reason of land degradation today.
  2. Deforestation is the another main reason of land degradation.

Question 10.
Why is land considered an important resource?
Answer:
Land is considered as an important resource because :

  1. It is used for different purposes such as agriculture, forest, mining, pastures, etc.
  2. Human beings make their houses and five on it and also it provides most of products they need like food, wood, etc.
  3. Human beings set up their industries, build roads and run other commercial activities.

Question 11.
What factors control the utilization of land?
Answer:
The physical and human factors control the utilization of land. These include :

  1. relief of features,
  2. climatic conditions,
  3. soils,
  4. density of population,
  5. technical level of the people,
  6. land tenure,
  7. duration of the occupation of the area etc.

The interplay of physical and human factors has developed many types of land uses.

Question 12.
What is terrace farming?
Answer:
Terrace farming: The growing of crops on level steps or terraces that have been constructed on hillsides.

Question 13.
What is a wildlife sanctuary?
Answer:
A wildlife sanctuary is dedicated to protect wildlife and conserve forests.

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 14.
What are the effects of deforestation?
Answer:
The effects of deforestation are as under :

  • It affects the ecosystem.
  • It increases soil erosion.
  • It affects underground flow of water.
  • Disappearance of wildlife as well as variety of plants.
  • Leads to serious deterioration of genetic reserves.

Question 15.
What are Protected forests?
Answer:
These are also forests reserved for timber but grazing is allowed subject to minor restrictions. These are 29.2% of total forests.

Question 16.
What is contour ploughing?
Answer:
Contour ploughing: Technique of ploughing parallel to the contours of a hill slope rather than up and down the slope, so as to reduce soil erosion.

Question 17.
What is strip cropping?
Answer:
Strip Cropping. Growing of different crops on parallel narrow strips of ground, usually following the contour patterns.

Question 18.
For what purposes land is used? What is land use pattern?
Answer:
Land is used for different purposes.

They are :

  • Cultivation of crops agriculture.
  • Grazing of animals.
  • Building houses and roads.
  • Mining.
  • Industries.

These uses of land is commonly termed as land use pattern.

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 19.
What is a shelterbelt?
Answer:
Shelterbelt: In dry regions, rows of trees are planted to check the wind movement for protecting soil cover.

Question 20.
Write the importance of forests.
Answer:
Importance of forests. Forests play an important role in human life. They provide food, wood and timber to us. Many medicinal plants are found in the forests. They also help in maintaining ecological balance and checking soil erosion. They play an important role in the economy of our country.

Question 21.
What is the role of insects in soil formation?
Answer:
Insects play a very important role in soil formation. Without worms and insects, the work of soil formation will be incomplete. They do it through both physical or mechanical means and speeding up chemical reactions.

Question 22.
Why does soil lose fertility?.
Answer:
The soil loses its fertility when continuously used. When crops are grown every year it loses its nutrients which are necessary for good soil.

Question 23.
What are the factors that control soil formation?
Answer:
Soil formation is controlled by five factors. These are :

  1. Nature of parent rock
  2. The topography
  3. The climate
  4. The organism in the soil
  5. Time.

Question 24.
What is the importance of landforms?
Answer:
Man’s economic activities differ with different landforms.

  1. Mountainous regions are not much suitable for human settlements.
  2. Dense population is found in plains.

Question 25.
‘Land plays a fundamental role.’ Discuss.
Answer:
Plains are known for agriculture and dense population. Plains, 43% area of India, fulfill man’s many needs. The agriculture depends upon plain.

Question 26.
What is fallow land?
Answer:
The land which is not used for agriculture for 1 to 5 years is left vacant. It restores the fertility of the soil. It is called fallow land.

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 27.
Examine the importance of water.
Answer:
Water is a valuable and important resource. It is the basis of life on earth. Water fulfils many human requirements. It is used for drinking, bathing, washing and agriculture.

Question 28.
Name the major threats to be environment.
Answer:
Land degradation, landslides, soil erosion and desertification are the major threats to the environment. This is because of expansion of agriculture and construction activities.

Question 29.
Write the steps that can help in conserving degraded land.
Answer:
The following steps may help in conservation and reclamation of degraded land:

  1. Afforestation and control on overgrazing.
  2. Plantation of land reclamation of plants.
  3. Regulated use of chemical pesticides and fertilisers.
  4. Proper discharge of sewage industrial effluents.
  5. Maintain proper mining processes and technique.

Fill in the blanks :

Question 1.
Nearly 97% of the earth’s total water is in the form of __________ and __________
Answer:
Sea, oceans

Question 2.
Tiger park at Dudhwa is situated in the state __________
Answer:
Uttar Pradesh

Question 3.
__________ is produced with the help of running and falling water.
Answer:
Hydro-electricity

Question 4.
Polar areas are populated areas.
Answer:
sparsely

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 5.
We can __________ the supply of drinking water by installing desalination plants.
Answer:
increase

Question 6.
In __________ areas landslides have been a major and widely spread natural disaster.
Answer:
mountains.

Long Answer Type Questions

Question 1.
What are the sources of fresh water in India? Describe each.
Answer:
Two types of water is found on earth-saline and fresh. Man uses freshwater for different purposes. Its sources are :
1. Rainfall. Rainfall is the major source of water on the earth. Some water is evaporated, some water flows down to the oceans and some water goes underground through percolation. India has average annual rainfall of 118 cm.
Rain water or running water flowing on the surface of land is called surface water. It includes water in oceans, seas, lakes, rivers, etc. India’s total surface water resources are 1869 billion cubic metres.

2. Ground Water. Rain water that goes beneath the surface of the earth by percolation is called ground water. India has a total ground water resources of 40 million hectare metres. This water can be obtained by digging wells. Sometimes it comes out through springs also.

3. Rivers and Canals. From early periods, rivers and canals have been very important. Many civilisations developed along river banks. Man built dams on rivers to use water for irrigation through canals.

4. Tanks. Tanks are found in areas deficit in rainfall. The water level is very deep so it is difficult to use it. Rain water is collected in depressions called tanks. Tanks are mostly found in southern India.

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 2.
What do you mean by Natural Vegetation? On what factors does it depend? Describe the different types of forests found in India.
Answer:
Natural vegetation includes plants and trees which grow automatically according to climate. It depends upon climate, soil, drainage, temperature, rainfall and altitude.

We can divide India into the following vegetation belts :

  • The Tropical Rain Forests.
  • The Tropical deciduous or the Monsoon forests.
  • The Thorn Forests.
  • The Tidal Forests.
  • Mountain Forests.

1. The Tropical Rain Forests are of two varieties: evergreen and semi-evergreen. Regions having more than 300 centimetres of rainfall have evergreen forests. The hills of Assam and the rainy slopes of the Western Ghats are such areas. The region where the rainfall is between 200 and 300 centimetres have semi-evergreen forests. Such areas are there in Assam, West Bengal, Orissa and in Western Ghats.

2. The Tropical Deciduous or Monsoon Forests are found in the regions where rainfall is between 100 and 200 centimetres. Teak and sal are the most important trees of monsoon forests besides sheesham, mahua, bamboo, etc. The belt of monsoon forests extends from the Western Ghats in the south to the Shiwalik hills in the north.

3. The Thorn Forests are found in Rajasthan, Haryana, Punjab, Gujarat, dry parts of Madhya Pradesh and the Deccan, where the rainfall is less than 80 centimetres. Kikar, Babool and Wild Palm are the common trees of this type of forests.

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources 6

4. The Tidal Forests are mainly found along the river deltas. Mangrove and Sundri trees are the common trees found in the Ganga delta in Bengal which is also “called the Sundarban.

5. The Mountainous Forests. The foothills of the Himalayas are covered with tropical deciduous forests. At high slopes, oak, chestnuts, chir, pine trees of sub-tropical type are formed. At a height of 3300 metres, coniferous forests like blue pines, cedars silver firs, deodars are found. Alpine pastures are found at high altitudes.

Question 3.
Write a short note on conservation of soils.
Answer:
Soil Conservation. Soil is a fundamental natural resource. Soil formation is a slow process, but it is easily lost by soil erosion. In fact, more soil is being lost each year than nature makes. Soil erosion must be checked. Sound farming practices and measures be adopted to conserve, protect, renew and maintain soil fertility.

These methods constitute soil conservation.
1. Afforestation: In some areas, the original vegetation cover has been removed such as in Shiwalik hills. In such areas afforestation and reforestation is needed to hold the soil. Advance of deserts can be checked by planting trees along the margins of deserts.

2. Controlled grazing: The number of cattle to be grazed on slopes should be according to the carrying capacity of the pastures.

3. Terraced agriculture: Slopes must be cut into a series of terraces (fields) for the cultivation so as to slow down the flow of rain water.

4. Contour Ploughing: It is done to check soil wash on slopes. Ploughing is done at right angles to the hill slopes.

5. Crop rotation: Crop rotation system be applied and the land should be allowed fallow for some time. Soil fertility can be maintained in this way.

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 4.
Distinguish between Evergreen Forests and Deciduous Forests.
Answer:

Evergreen Forests Deciduous Forests
1. Evergreen forests are found in regions that experience tropical climate throughout the year. 1. Deciduous forests are found in regions that experience rainy and dry season.
2. They do not shed their leaves in any season of the year. 2. They shed their leaves once a year.
3. Their height exceeds 60 metres. 3. They are less than 50 metres in height.
4. They have less economic importance as the wood from them is very hard and is of not much use. 4. They have more economic value, as their wood is soft and durable.
5. Some trees are ; Rosewood, Mahogany etc. 5. Some trees are ; Teak, Sal, etc.

Question 5.

What is the most important feature of the Landuse pattern in India?
Answer:

  1. India has total geographical area of 828 million sq. km. (3280 lakh hectares). The land use data is available for about 93% of the total area. It shows that 151 million hectares (47%) is net sown area. Thus India has a very high percentage (47%) of total area under cultivation. No other big country has such a large area under cultivation.
  2. Another satisfying feature is that only 8% of land is fallow which is not cultivated so as to restore the fertility of the land. It is notable that fallow land has risen to 8% from earlier figure of 5%. It reflects that care for land resources has become essential.
  3. The area under pastures is also small (4%).
  4. The area under cultivable waste is 5%. This wasteland can be brought under cultivation to increase productivity.
  5. The forest cover is low, only 22%. It is desirable to have about one third of the total land area under forests to maintain a healthy environment.

Question 6.
Explain the factors controlling soil formation.
Answer:
Soil formation is controlled by five factors :

  1. nature of parent rock,
  2. the topography,
  3. the climate,
  4. the organism in the soil and
  5. time.

1. Parent Rock: The original rock called parent rock, from which the soil is formed, determines its basic characteristics. For example, shales contribute clays, while sandstones contribute sand grains.

2. Climate: Temperature and precipitation are the main climatic factors affecting soil formation. Frequent temperature changes and presence of water quicken soil formation through increased weathering.

3. Topography: Topography affects the drainage of an area. On a steep slope, there is hardly any chance of accumulation of weathered rocks. They are moved down the slope by water and under force of gravity. In plains and areas with gentle slope, soils are accumulated without any hindrance.

4. Organisms: Dead plants and animals provide humus to soil. Organisms like earthworms and ants through their movements create space for air and water in the soil.

5. Time: Time factor is also important because longer the time for soil formation, more deeper is the soil layer. Besides weathering of rocks, soil is also formed by deposition of materials by moving waters (rivers) and winds in low-lying areas. Alluvial soils of river valleys are very fertile and deep.

Question 7.
What are water resources? What are their uses?
Answer:
Water Resources. Water is a unique liquid because there is no alternative for it. It is essential for all forms of life. Compared to most other liquids, water has a high capacity to absorb or store heat.

Water is a major body constituent of several plant and animal species. Seventy percent of the human body consists of water. Humans use water for several purposes—domestic (drinking, cooking, washing, etc.), agricultural (irrigation), industrial and generation of electricity.

PSEB 8th Class Social Science Solutions Chapter 2 Natural Resources

Question 8.
How are vegetation and wildlife useful for us?
Answer:
Vegetation and wildlife are valuable resources
1. Plants provide us

  • Timber, fruits, nuts, latex, oil, gum, medicinal herbs, etc.
  • Shelter for animals and birds.
  • Protect soil and storage and water.
  • Oxygen to breathe.

2. Wildlife provides us

  • with milk, meat, hides, wool, honey.
  • helps as decomposers, act as scavengers.
  • maintain the ecological balance.
  • The birds feed on insects and act as decomposers as well.
  • Vulture each dead livestock and act as scavengers. They are considered as a vital cleaner of environment.

PSEB 8th Class Science Solutions Chapter 6 Combustion and Flame

by

Punjab State Board PSEB 8th Class Science Book Solutions Chapter 6 Combustion and Flame Textbook Exercise Questions and Answers.

PSEB Solutions for Class 8 Science Chapter 6 Combustion and Flame

PSEB 8th Class Science Guide Combustion and Flame Textbook Questions and Answers

Exercises

Question 1.
List conditions under which combustion can take place.
Answer:
Conditions necessary for combustion:

  1. Presence of a combustible substance.
  2. Presence of a supporter of combustion.
  3. Attainment of ignition temperature.

Question 2.
Fill in the blanks.
(a) Burning of wood and coal causes ……………… of air.
(b) A liquid fuel, used in homes is ………………
(c) Fuel must be heated to its …………………………………… before it starts burning.
(d) Fire produced by oil cannot be controlled by …………………..
Answer:
(a) Pollution.
(b) Kerosene.
(c) Ignition temperature.
(d) Water.

PSEB 8th Class Science Solutions Chapter 6 Combustion and Flame

Question 3.
Explain how the use of CNG in automobiles has reduced pollution in our cities.
Answer:
CNG is a clean gaseous fuel. It burns completely in air and does not produce any harmful gases. So, the use of CNG in automobiles has reduced pollution in our cities.

Question 4.
Compare LPG and wood as fuels.
Answer:
LPG is a clean fuel. It is liquefied petroleum gas and is filled in cylinders. It burns with a blue flame and leaves no residue. Its calorific value is high. Wood is not a clean fuel. It burns and release lots of smoke and ashes are left behind. It give very low amount of heat.

Question 5.
Give reasons:
(a) Water is not used to control fires involving electrical equipment.
(b) LPG is a better domestic fuel than wood.
(c) Paper by itself catches fire easily whereas a piece of paper wrapped around an aluminium pipe does not.
Answer:
(a) The substance used for extinguishing fires on electrical appliances or circuit should not be good conductor of electricity as there are chances of electrocution. So, water being a good conductor of electricity, is not used for extinguishing fires on electrical appliances or circuit. Carbon-tetrachloride (non-electrolyte) is used for this purpose.

(b) LPG is liquefied petroleum gas. It has high calorific value of 50 kJ/g. It is neat and clean fuel. It burns with a smokeless flame and does not produce poisonous gases. While wood has less calorific value of 17 kJ/g. It gives out smoke and poisonous gases on burning. So, LPG is better fuel than wood.

(c) When paper wrapped around an aluminium pipe is brought near a flame, it does not burn because the heat gets transferred to aluminium pipe and the ignition temperature of paper is not achieved.

Question 6.
Make a labelled diagram of a candle flame.
Answer:
PSEB 8th Class Science Solutions Chapter 6 Combustion and Flame 1

Question 7.
Name the unit in which the calorific value of a fuel is expressed.
Answer:
Kilojoules per kilogram (kJ/kg).

Question 8.
Explain how CO2 is able to control fires.
Answer:
CO2 gas is heavier than air. So, it forms an envelope around the burning fire. This, cuts off the supply of oxygen gas and fire stops burning and gets under control.

Question 9.
It is difficult to burn a heap of green leaves but dry leaves catch fire easily. Explain.
Answer:
Green leaves have a high moisture content in them and in the heap of green leaves, oxygen present is very less. Whereas dry leaves have no moisture content and there is lot of oxygen available in this heap. So, it is difficult to burn a heap of green leaves than a heap of dry leaves.

PSEB 8th Class Science Solutions Chapter 6 Combustion and Flame

Question 10.
Which zone of flame does a goldsmith use for melting gold and silver and why ?
Answer:
Goldsmith usually uses the upper most, non-luminous, blue flame for melting gold and silver because it is the hottest part of the flame.

Question 11.
In an experiment 4.5 kg of a fuel was completely burnt. The heat produced was measured to be 180,000 kJ. Calculate the calorific value of the fuel.
Solution:
Mass of fuel = 4.5 kg
Heat produced = 180,000 kg
Now, Calorific value of a substance = \(=\frac{\text { Heat produced }}{\text { Mass }}\)
= \(\frac{180,000}{4 \cdot 5}\) kj/kg
= \(\frac{40,000}{1}\)
= 4 × 104 kj/kg

Question 12.
Can the process of rusting be called combustion ? Discuss.
Answer:
Rusting.
When iron is exposed to moist air, it gets coated with hydrated iron oxide. This process is called rusting and the coating formed is called rust. Chemically rust is hydrated form of ferric oxide, Fe2O3. xH2O. It is reddish brown in colour.
The overall reaction for rusting is:
PSEB 8th Class Science Solutions Chapter 6 Combustion and Flame 2
Combustion is an oxidation reaction and rusting is also an oxidation reaction but very slow. So, rusting can be termed as slow combustion reaction.

Question 13.
Abida and Ramesh were doing an experiment in which water was to be heated in a beaker. Abida kept the beaker near the wick in the yellow part of the candle flame. Ramesh kept the beaker in the outermost part of the flame. Whose water will get heated in a shorter time.
Answer:
Ramesh’s beaker will get heated in a shorter time because the outermost part of flame is the hottest part.

PSEB Solutions for Class 8 Science Combustion and Flame Important Questions and Answers

Multiple Choice Questions

Question 1.
With the help of the following diagram tell the colour of its flame?
PSEB 8th Class Science Solutions Chapter 6 Combustion and Flame 3
Answer:
The colour of the flame of lamp: yellow
The colour of the flame of candle : yellow
The colour of the flame of bunsen burner : blue.

Question 2.
In the figure below various parts of candle flame are given. Tell which one of them is less hot ?
PSEB 8th Class Science Solutions Chapter 6 Combustion and Flame 4
(а) Outer Zone
(б) Inner Zone
(c) Middle Zone
(d) None of these.
Answer:
(c) Middle Zone.

Question 3.
Fuel is:
(a) Solid
(b) Liquid
(e) Gas
(d) Solid, liquid and gas
Answer:
(d) Solid, liquid and gas

Question 4.
Which of the following gas is supporter in combustion?
(a) Oxygen gas
(b) L.P.G.
(e) Nitrogen gas
(d) Carbondioxide gas
Answer:
(a) Oxygen gas.

PSEB 8th Class Science Solutions Chapter 6 Combustion and Flame

Question 5.
Which of the following is combustible substance ?
(a) Iron nail
(b) Glass
(c) Paper
(d) A piece of stone
Answer:
(c) Paper

Question 6.
The conditions for combustion are:
(a) Fuel and air
(b) Fuel, air and ignition temperature
(c) Fuel and ignition temperature
(d) Air and ignition temperature.
Answer:
(b) Fuel, air and ignition temperature.

Question 7.
Which out of the following has minimum ignition temperature ?
(a) Petrol
(b) Kerosene
(c) Coal
(d) L.P.G.
Answer:
(d) L.P.G.

Question 8.
Which of the following gas causes acid rain ?
(a) H2
(b) N2
(c) Carbon-monoxide
(d) Oxides of sulphur and nitrogen
Answer:
(d) Oxides of sulphur and nitrogen.

Question 9.
While extinguishing fire of electric wires and electric instruments, which of the following item is not used ?
(a) Sand
(b) Water
(c) Foam
(d) Carbondioxide
Answer:
(b) Water.

Question 10.
The unit of Calorific value of a fuel is:
(a) Joule
(b) Kilo joule/kg
(c) Kilo joule
(d) None of the above.
Answer:
(b) Kilo joule/kg.

Very Short Answer Type Questions

Question 1.
List the fuels used in rural areas in our country.
Answer:
Wood, agricultural wastes and cow-dung cakes.

PSEB 8th Class Science Solutions Chapter 6 Combustion and Flame

Question 2.
Which of the following solid fuels has the highest heat value: Cow-dung cakes, coal, wood?
Answer:
Coal.

Question 3.
Name the most commonly used liquid fuel in Indian homes.
Answer:
Kerosene.

Question 4.
Name three liquid fuels.
Answer:
Kerosene oil, Petrol, Diesel.

Question 5.
When fuels burn, what do they produce?
Answer:
Heat and light.

Question 6.
What is ignition temperature?
Answer:
Ignition temperature. The lowest temperature at which a substance catches fire in the presence of oxygen, is called its ignition temperature.

Question 7.
Name two liquids which have low ignition temperatures.
Answer:

  1. Alcohol and
  2. ether.

Question 8.
What type of fire èxtinguisher is used to extinguish fire caused by
electricity?
Answer:
Carbon tetrachioride (CCl4) fire extinguisher.

PSEB 8th Class Science Solutions Chapter 6 Combustion and Flame

Question 9.
What is combustion ?
Answer:
Combustion.
It is the process of heating of a substance in the presence of oxygen with the evolution of heat and light.
It is an oxidation reaction in which substance (fuel) burns in the presence of oxygen so as to liberate heat and light.

Question 10.
Define heat value of a fuel.
Answer:
Heat value of fuel. The amount of heat liberated when 1 kg of substance is burned, is called heat value of that fuel.

Question 11.
Name the type of fire extinguisher used for extinguishing oil fires.
Answer:
Foam type fire extinguisher.

Question 12.
Why charcoal is considered better fuel than wood ?
Answer:
It is because calorific value of charcoal is higher than that of wood.

Question 13.
Name the zones of a candle flame.
Answer:

  1. Cold innermost zone,
  2. middle zone,
  3. outermost non-luminous zone.

Question 14.
Name two substances which may be effective in fire fighting.
Answer:
Water and Foam.

Question 15.
Name three combustible substances.
Answer:
Paper, wood and cooking gas are three combustible substances.

PSEB 8th Class Science Solutions Chapter 6 Combustion and Flame

Short Answer Type Questions

Question 1.
What are fuels ? In which different states fuels are found?
Answer:
Fuels. The materials which are burnt to produce heat and light, are called
fuels.
Fuels are found in three states:

  1. Solid (wood, coal, charcoal etc.)
  2. Liquid (petrol, kerosene, diesel)
  3. Gases (natural gas, coal gas, bio-gas etc).
    Fuels are found in Maharashtra and Gujarat states.

Question 2.
How will you prove that air is required for combustion?
Answer:
A burning coal or wood piece stops burning after some time, if it is covered with a glass vessel. This is because the supply of air is cut off, which stops combustion. If air is blown on this burning piece, it again starts burning with a blaze. It is therefore, concluded that air (supporter of combustion) is required for burning of a substance.

Question 3.
How can accidental fires be extinguished?
Answer:
Accidental fires can be extinguished by controlling any one of the three conditions responsible for producing fire:

  1. by cutting supply of air (oxygen) so that the combustible substance does not come in contact with the supporter of combustion.
  2. by cooling the burning substance or by lowering its ignition temperature.
  3. by removing nearby combustible substances so that fire does not spread.

Question 4.
Why do Goldsmiths use a blow-pipe?
Answer:
Goldsmiths use a blow-pipe to intensify a kerosene lamp flame for moulding pieces of gold or silver into desired shapes. The air blown through the pipe aids combustion of unburnt particles of fuel, thereby making the flame hotter.

Question 5.
Why do combustible substances not catch fire on their own ?
Answer:
Combustible substances cannot catch fire on their own as their ignition temperature is higher than normal temperature. When the temperature is lowered than ignition temperature, they catch fire.

Question 6.
Explain Ignition temperature, combustible substance, supporter of combustion in reference to conditions of combustion.
Answer:
Ignition temperature is the minimum temperature at which fuel catches fire. Each substance has definite ignition temperature below which it will not catch fire.

Combustible substance is that which readily catches fire. Paper, LPG, cloth etc. are combustible substances.

Supporter of combustion is that substance which helps in burning the combustible substance. Combustible substances like petrol, LPG will not burn till supporter of combustion like oxygen is supplied in ample amount.

Question 7.
Given the reaction:
C + O2 → CO2 + 385 kJ
Calculate the calorific value of carbon (atomic weight of C = 12, O = 16).
Solution:
According to equation, 1 mole of carbon or 12 g of carbon on burning produce 385 kJ of heat.
Thus
12 g of carbon produce heat = 385 kJ
1 g of carbon produces heat = \(\frac{385}{12}\)
∴ Calorific value of carbon = 32.1 kJ/g

PSEB 8th Class Science Solutions Chapter 6 Combustion and Flame

Question 8.
Why is a match stick lighted on rubbing it on the rough surface provided on the side of the match box ?
Answer:
This is due to the fact that when we rub the match stick on the rough surface of the match box, the work done during rubbing produces heat due to friction. This heat raises the temperature of the chemical present on the match stick head to its ignition temperature. Therefore, the chemical substance catches fire and the match stick starts burning.

Question 9.
Why is coke considered a better fuel than coal ? Give four reasons.
Answer:
Coke is considered a better fuel than coal because of the following reasons:

  1. Coke has higher calorific value than coal.
  2. Ignition temperature of coke is less than that of coal.
  3. Coke produces less smoke than coal.
  4. Coal on burning produces some pollutants like CO2, CO and small quantities of SO2 whereas coke does not
    produce these pollutants.

Question 10.
What do you mean by fire fighting ?
Answer:
Fire Fighting.
By fire fighting we mean to put out the fire. A fire may be due to an accident, short circuiting or human negligence. The combustion of a substance requires combustible substances, oxygen (or air) and heat. Therefore, to put out fire the air or oxygen supply should be cut off.

Question 11.
What should you do to put out the fire ?
Answer:
A fire may be due to an accident, short circuiting or human negligence. The combustion of a substance requires combustible substance, oxygen and heat. Therefore, to put out fire the air supply should be cut off. The fire can be put out by using carbon dioxide, water, sand etc.

Question 12.
Why should water not be used to extinguish fire due to :
(i) Kerosene or Petrol
(ii) Short circuiting ?
Answer:
(i) This is because kerosene and petrol being lighter than water, float on it and may further spread fire.

(ii) This is because water conducts electricity and it can cause a fatal shock to the person who is putting out the fire.

Question 13.
Why do we wrap a blanket around a person who has caught in lire ?
Answer:
When a person is caught in fire is wrapped with blanket does not get proper supply of oxygen which is necessary for combustion to take place.

Question 14.
Why are we advised not to sleep in a room with a burning coal ingithi in it ?
Answer:
In a closed room there is limited supply of oxygen and due to incomplete combustion of coal, carbon monooxide gas is produced. This gas is poisonous and may prove fatal. So we are advised not to sleep in a closed room with burning coal ingithi in it.

PSEB 8th Class Science Solutions Chapter 6 Combustion and Flame

Question 15.
Explain Global warming.
Answer:
Global Warming. Combustion of most fuels releases carbondioxide in the air resulting in the increase of temperature of the atmosphere which is believed to be the cause of Global warming. Global warming results in melting of polar glaciers causing floods in the low lying coastal areas.

Question 16.
What is acid rain ?
Answer:
Acid Rain.
Burning of coal and diesel releases sulphur dioxide gas which is very pungent and suffocating. Moreover, petrol engines give off oxides of nitrogen. These oxides of sulphur and nitrogen dissolve in water of rain to form acids. Such rain is called Acid rain.

Question 17.
Why does the flame shown in the picture extinguishes when a glass jar is put on the burning candle ?
PSEB 8th Class Science Solutions Chapter 6 Combustion and Flame 5
Answer:
We know that oxygen is necessary for burning but when we put a glass jar on the burning candle, the amount of oxygen becomes less. The flame of candle extinguishes because of shortage of oxygen.

Long Answer Type Questions

Question 1.
Discuss the various combustion zones of a candle flame with the help of a diagram.
or
Explain the zones of candle with the help of a diagram.
Answer:
PSEB 8th Class Science Solutions Chapter 6 Combustion and Flame 6
A candle flame has three distinct zones.
1. Dark inner Zone
2. Luminous Zone
3. Non-luminous Zone.

1. Dark inner zone.
The innermost zone is dafk and is the coldest part of the flame. It consists largely of the hot vapours of wax (the combustible material). Introduce one end of a glass tube in the zone, you will see white vapours coming out from the other end of the tube. On being lighted with a matchstick, these emerging vapours burn with a flame.

2. Luminous Zone.
The middle zone is a bright luminous zone. In this zone the fuel partially burns forming carbon particles. It is the glow of these particles that makes this zone luminous. The carbon particles leave the flame as smoke and soot.

3. Non-luminous Zone.
It is the outer zone which is faintly bluish in colour. In this zone oxygen from the air mixes with the fuel bringing about complete combustion. This zone is the outermost non-luminous zone. It has the highest temperature of around 1800°C.

Question 2.
Describe
(i) Rapid combustion
(ii) Spontaneous combustion
(iii) Slow combustion
(iv) Explosion.
Answer:
(i) Rapid Combustion.
The oxidation reaction in which heat and light is produced in a short time is called rapid combustion. For example, when a burning splinter is brought near the gas burner, the gas tap of which is opened, the gas immediately starts burning with the production of heat and light. Similarly, a candle starts burning when a burning splinter is brought close to its wick.

(ii) Spontaneous Combustion.
Combustion which takes place without the application of any external heat is known as spontaneous combustion.
White phosphorus is the best example of a substance burning with spontaneous combustion.

(iii) Slow Combustion.
It is a slow oxidation process in which no light is produced. In such a reaction the heat liberated is at such a low rate that we cannot feel it.
Rusting of iron and the process of respiration are examples of slow combustion.

(iv) Explosion.
Such a process of combustion, where a large number of gases with the evolution of the tremendous amount of heat and light are evolved is called an explosion. During the Diwali festival, we observe that certain crackers explode only when pressure is applied. In this process, the oxidation of the chemicals in the cracker takes place at a very high speed. Large amounts of gases are liberated with the evolution of a tremendous amount of heat and light.
Gunshot, when fired, is called an explosion.

PSEB 8th Class Science Solutions Chapter 2 Microorganisms: Friend and Foe

by

Punjab State Board PSEB 8th Class Science Book Solutions Chapter 2 Microorganisms: Friend and Foe Textbook Exercise Questions and Answers.

PSEB Solutions for Class 8 Science Chapter 2 Microorganisms: Friend and Foe

PSEB 8th Class Science Guide Microorganisms: Friend and Foe Textbook Questions and Answers

Exercises

Question 1.
Fill in the blanks:
(а) Micro-organisms can be seen with the help of a ……………. .
Answer:
microscope

(b) Blue green algae fix ……………….. directly from air to enhance fertility of soil.
Answer:
nitrogen

(c) Alcohol is produced with the help of …………………
Answer:
yeast

(d) Cholera is caused by ……………. .
Answer:
bacteria

PSEB 8th Class Science Solutions Chapter 2 Microorganisms: Friend and Foe

Question 2.
Tick the correct answer:
(a) Yeast is used in the production of:
(i) sugar
(ii) alcohol
(iii) hydrochloric acid
(iv) oxygen.
Answer:
(ii) alcohol

(b) The following is an antibiotic :
(i) Sodium bicarbonate
(ii) Streptomycin
(iii) Alcohol
(iv) Yeast.
Answer:
(ii) streptomycin.

(c) Carrier of malaria-causing protozoan is:
(i) female anopheles mosquito
(ii) cockroach
(iii) housefly
(iv) butterfly.
Answer:
(i) female anopheles mosquito.

(d) The most common carrier of communicable diseases is :
(i) ant
(ii) housefly
(iii) dragonfly
(iv) spider.
Answer:
(ii) housefly.

(e) The bread of idli dough rises because of:
(i) heat
(ii) grinding
(iii) growth of yeast cells
(iv) kneading.
Answer:
(iii) growth of yeast cell.

(f) The process of conversion of sugar into alcohol is called:
(i) nitrogen fixation
(ii) moulding
(iii) fermentation
(iv) infection.
Answer:
(iii) fermentation.

Question 3.
Match the organisms in Column ‘A’ with their action in Column ‘B’

Column A Column B
(i) Bacteria (a) Fixing nitrogen
(ii) Rhizobium (b) Setting of curd
(iii) Lactobacillus (c) Baking of bread
(iv) Yeast (d) Causing malaria
(v) A protozoan (e) Causing cholera
(vi) A virus (f) Causing AIDS
(g) Producing antibodies

Answer:

Column A Column B
(i) Bacteria (а) Causing cholera
(ii) Rhizobium (b) Fixing nitrogen
(iii) Lactobacillus (c) Setting of curd
(iv) Yeast (d) Baking of bread
(v) A protozoan (e) Causing malaria
(vi) A virus (f) Causing AIDS

PSEB 8th Class Science Solutions Chapter 2 Microorganisms: Friend and Foe

Question 4.
Can micro-organisms be seen with the naked eye ? If not, how can they be seen ?
Answer:
No, micro-organisms cannot be seen with naked eye because they are too small. So, we can only see them under microscope.

Question 5.
What are the major groups of micro-organisms ?
Answer:
The various groups of micro-organisms are:

  1. Bacteria
  2. fungi
  3. protozoa
  4. algae
  5. virus.

Question 6.
Name the micro-organisms which can fix atmospheric nitrogen in the soil.
Answer:

  1. Rhizobium bacteria
  2. Blue green algae.

Question 7.
Write 10 lines on the usefulness of microorganisms in our lives.
Answer:
Micro-organisms are bacteria, fungi, algae and protozoans. The beneficial aspects of Micro-organisms are as given ahead:
Beneficial aspects of Bacteria:

  1. Formation of milk products like curd and cheese.
  2. Tenderization of meat by breaking down tough muscle fibre.
  3. Formation of vinegar and wines.
  4. Decomposition of organic matter.
  5. Tanning of leather.
  6. Conversion of atmospheric nitrogen to usable nitrogenous compounds.

Beneficial aspects of Fungi:

  1. Production of bakery products like bread and cakes.
  2. Other products like idli, dosa, processed cheese, etc.
  3. Beverages like wines, beers, etc.
  4. Mushrooms are edible fungi.
  5. Medicines such as penicillin are made from fungi.

Beneficial aspects of Algae:
They help in the production of organic matter through photosynthesis which provides food to aquatic animals.

  1. Algae cell extracts like agar and alginic acid are used for preparing medicines, food and cosmetics, etc. Kelp that is a brown algae is a rich source of iodine and potassium.
  2. The cell walls of diatom (an alga) are a natural source of fine silica.
  3. Many sea weeds are used as food in China and Japan.

Beneficial aspects of Protozoans:

  1. They form an important link in the food chain.
  2. They feed on fungi and bacteria. Mix it with potato glucose solution prepared earlier. Store the mixture so obtained in the suitable container. The PDA medium is ready and can now be used to culture microorganisms in petri dishes or test tubes.

Question 8.
Write a short paragraph on the harms caused by microorganisms.
Answer:
Harmful effects of Microorganisms:
1. These microorganisms cause a large variety of diseases in plants, animals and human beings.
2. They spoil food items as well as other articles like clothes, leather etc.
3. Micro-organisms spoil food by:

  • breaking down its molecules and make new products called (amines) which are generally smelly. This changes its chemical composition as well as its texture and physical appearance.
  • some microbes secrete poisonous substances called toxins which if consumed lead to food poisoning.
  • micro-organisms grow in the food and sometimes form a whole colony consisting of such large numbers that this food, if consumed can cause illness. It is called food poisoning.

Question 9.
What are antibiotics ? What precautions must be taken while taking antibiotics ?
Answer:
Antibiotics. These are those chemical secretions which are secreted by certain microorganisms and inhibits the growth of other microorganisms without harming the host.
Alexander Fleming, an English scientist in 1929, discovered Penicillin.
Precautions to be taken while taking antibiotics
Given ahead precautions should be taken while taking antibiotics:

  1. Antibiotics should be taken only on the advice of a qualified doctor,
  2. You must finish the course prescribed by the doctor,
  3. Antibiotics, however, are not effective against cold and flu as they are caused by viruses.

PSEB Solutions for Class 8 Science Microorganisms: Friend and Foe Important Questions and Answers

Multiple Choice Questions

Question 1.
The following slide shows which micro-organism ?
PSEB 8th Class Science Solutions Chapter 2 Microorganisms Friend and Foe 1
(a) Spirogyra
(b) Amoeba
(c) Bacteria
(d) Fungi on bread.
Answer:
(c) Bacteria.

PSEB 8th Class Science Solutions Chapter 2 Microorganisms: Friend and Foe

Question 2.
Is of which micro-organism is shown in the diagram ?
PSEB 8th Class Science Solutions Chapter 2 Microorganisms Friend and Foe 2
(a) Spirogyra
(b) Amoeba
(c) Bacteria
(d) Fungi on bread
Answer:
(c) Bacteria

Question 3.
The slide which is being shown below with the help of microscope is of which micro-organism ?
PSEB 8th Class Science Solutions Chapter 2 Microorganisms Friend and Foe 3
(a) Amoeba
(b) Bacteria
(e) Paramecium
(d) Virus
Answer:
(d) Virus.

Question 4.
Which of the following micro-organisms can be seen only with the help of microscope ?
(a) Virus
(b) Bacteria
(c) Yeast
(d) All of the above.
Answer:
(d) All of the above.

Question 5.
Today the teacher in the class showed a slide to his students with the help of microscope. To which micro-organism does this slide belong ?
PSEB 8th Class Science Solutions Chapter 2 Microorganisms Friend and Foe 4
(a) Amoeba
(b) Bacteria
(e) Paramecium
(d) Penciliam
Answer:
(c) Paramecium.

Question 6.
For what purpose yeast is used ?
(a) Sugar
(b) Wine
(c) Hydrocloride Acid
(d) Oxygen
Answer:
(b) Wine

Question 7.
Which of the following is antibiotics ?
(a) Sodium Bicarbonate
(b) Streptomycin
(c) Alcohol
(d) Yeast
Answer:
(b) Streptomycin.

Question 8.
The carrier of malaria-causing protozoan is:
(a) Female anopheles mosquito
(b) Cockroach
(c) Housefly
(d) Butterfly
Answer:
(a) Female anopheles mosquito.

PSEB 8th Class Science Solutions Chapter 2 Microorganisms: Friend and Foe

Question 9.
The most common carrier of communicable diseases is:
(a) Ant
(6) Housefly
(c) Dragonfly
(d) Spider.
Answer:
(b) Housefly

Question 10.
The bread or idli dough rises because of:
(a) Heat
(b) Grinding
(c) The growth of yeast cells
(d) Kneeding
Answer:
(c) The growth of yeast cells.

Question 11.
The process of conversion of sugar into alcohol is called:
(a) Nitrogen fixation
(b) Moulding
(c) Fermentation
(d) Infection.
Answer:
(c) Fermentation.

Question 12.
Which instrument is used to see micro-organisms ?
(a) Magnifying glass
(b) Microscope
(c) Telescope
(d) All the above.
Answer:
(b) Microscope.

Question 13.
Which of the following micro-organisms is responsible for causing cholera ?.
(a) Virus
(b) Protozoa
(c) Bacteria
(d) None of these.
Answer:
(c) Bacteria.

Very Short Answer Type Questions

Question 1.
Fill in the blanks:

1. Microorganisms can be seen with the aid of ……………….. .
Answer:
microscope

2. Bacteria normally multiply by ……………….. .
Answer:
binary fission

PSEB 8th Class Science Solutions Chapter 2 Microorganisms: Friend and Foe

3. Disease producing microbes are called ……………….. .
Answer:
pathogens

4. The poisonous substances produced by some pathogenic bacteria are known as ……………… .
Answer:
toxins

5. Algae can make their own food because they can ………………… .
Answer:
photo- synthesise

6. The chief source of food for fishes is ……………….. .
Answer:
algae

7. The product of algae used for raising bacterial culture is called ……………….. .
Answer:
agar

8. Algae are plant-like but ……………….. are animal-like.
Answer:
protozoans

9. Mushroom is a type of ………………. .
Answer:
fungus

10. Microorganisms which form the borderline between the living and nonliving world are called …………..
Answer:
viruses

PSEB 8th Class Science Solutions Chapter 2 Microorganisms: Friend and Foe

Question 2.
Define microscope.
Answer:
Microscope. It is an optical instrument which enables us to see the very tiny organisms called microorganisms.

Question 3.
Which micro-organism lies on the borderline dividing the living world from the non-living ?
Answer:
Virus lies on the borderline dividing the living and non-living.

Question 4.
Name four antibiotics.
Answer:
Penicillin, Streptomycin, Tetracycline and Gramicidin.

Question 5.
What are micro-organisms ?
Answer:
Micro-organisms. These are small organisms which are too small to be seen with naked eyes.

Question 6.
Name the major groups of micro organisms.
Answer:
The major groups of microorganisms are:
Bacteria, Fungi, Protozoa, Algae and Viruses.

Question 7.
Write the average size of bacterium.
Answer:
1.25 mm (1μm = \(\frac{1}{1000}\) mm) in diameter.

Question 8.
Which is the smallest bacteria ?
Answer:
The smallest is rod-shaped bacteria measuring 0.15 mm.

Question 9.
Name the largest bacteria.
Answer:
Spiral shaped bacteria measuring upto 15 mm in length and 1.5 μm in diameter.

PSEB 8th Class Science Solutions Chapter 2 Microorganisms: Friend and Foe

Question 10.
Name two examples of Bacillus.
Answer:
Lactobacillus, Pseudomonas.

Question 11.
Write examples of blue-green algae.
Answer:
Nostoc, Anabaena, Oscillatoria.

Question 12.
How much nitrogen is fixed by blue-green algae in a paddy field in a year ?
Answer:
About 625 kg of nitrogen in one square km area.

Question 13.
Which micro-organism is used in the preparation of bread and alcohol ?
Answer:
Yeast.

Question 14.
Name two nitrogen fixing algae.
Answer:
Nostoc and Anabaena.

Question 15.
What are the two major groups of fungi ?
Answer:
Yeast and moulds.

Question 16.
Under which group of micro-organisms Amoeba fall ?
Answer:
Protozoa.

Question 17.
Name two antibiotics.
Answer:

  1. Streptomycin
  2. Erythromycin.

PSEB 8th Class Science Solutions Chapter 2 Microorganisms: Friend and Foe

Question 18.
Who discovered vaccination ?
Answer:
Louis Pasteur.

Question 19.
Name unicellular micro-organism.
Answer:
Bacteria, Protozoa.

Question 20.
Name multicellular micro-organisms.
Answer:
Algae, Fungi.

Question 21.
Name a micro-organism which can live independently.
Answer:
Amoeba.

Question 22.
Name micro-organisms which live in groups.
Answer:
Fungi and Bacteria.

Question 23.
For which purpose antibiotics are used ?
Answer:
Antibiotics are used for curing diseases.

Question 24.
Which micro-organisms are used to prepare antiboitics ?
Answer:
Bacteria and Fungi.

Question 25.
When and who first invented first antiboitic ?
Answer:
Alexander Fleming in 1929, invented first antibiotic.

PSEB 8th Class Science Solutions Chapter 2 Microorganisms: Friend and Foe

Short Answer Type Questions

Question 1.
Are all micro-organisms of similar sizes ?
Answer:
No, all micro-organisms are not of similar size. The size of bacteria ranges from 0.2 to 100 microns. The size of yeast ranges from 5 to 10 micron and that of moulds from 2 to 10 micron. The size of algae ranges from 1 micron to several metres in length. The size of protozoa ranges from 2 to 200 microns. The size of viruses ranges from 0.015 to 0.2 micron.

Question 2.
Give examples of a slow and fast growing bacteria.
Answer:
Examples of slow growing bacteria:

  1. Mycobacterium tuberculi
  2. Mycobacterium leprae

Examples of fast growing bacteria:

  1. Pseudomonas
  2. E. coli.

Question 3.
What are the two groups of organisms of fungi ?
Answer:
Fungi consists of two main groups:
Yeasts and Moulds.

  1. Yeasts. They are usually unicellular.
  2. Moulds. They are usually multicellular and have a filament-like appearance.

Question 4.
How do microbes survive adverse conditions ?
Answer:
Micro-organisms are very hardy. They can survive under extreme conditions of temperature and dryness by forming a hard outer coating called a cyst. Within this protective shell, they remain inactive as such, until more favourable conditions return. They, then emerge from their shell, multiply and go through their life cycles.

Question 5.
In what ways, are viruses different from other microbes ? Name two plant viruses and two animal viruses.
Answer:
Viruses are different from other microbes due to the following facts:
1. They are the smallest microbes.
2. They cannot be totally called living beings because they do not grow on their own.
3. They are mostly harmful and cause a number of diseases.

Plant viruses.

  1. Tobacco mosaic virus (TMV)
  2. Bacteriophage.

Animal viruses.

  1. Foot and mouth disease virus (FMDV)
  2. Measle virus.

Question 6.
Why are viruses placed on the border line between living and nonliving things ?
Answer:
Viruses resemble living objects due to following reasons:

  1. They contain nucleic acids.
  2. They grow and multiply like living beings.

Viruses resemble non-living things due to the following reasons:

  1. They do not contain cytoplasm and definite nucleus.
  2. They can be crystallized like salts or sugar.

Question 7.
Differentiate between yeasts and moulds.
Answer:
Differences between Yeasts and Moulds

Yeasts Moulds
1. They are unicellular. 1. They are multi-cellular.
2. They range in size from 5-10 microns. 2. They range in size from 2-10 microns.
3. Yeasts are both aerobic as well as anaerobic. 3. Moulds are aerobic.

PSEB 8th Class Science Solutions Chapter 2 Microorganisms: Friend and Foe

Question 8.
Write some examples of commercial products obtained from fungi.
Answer:

  1. Some fungi are directly used in the preparation of dishes.
  2. Some antibiotics are obtained from fungus.
  3. Some fungi are used in the preparation of bread and alcohol.
  4. Wines, beers are prepared with the help of certain fungi.

Question 9.
What are Bacteriophages ?
Answer:
Bacteriophage. Viruses are heterotrophic. Virus which depend on bacteria are called bacterial viruses or bacteriophages.
It is shaped like a rod. They destroy bacteria which are responsible for spoilage of organic matter.
PSEB 8th Class Science Solutions Chapter 2 Microorganisms Friend and Foe 5

Question 10.
Describe the various products involving action of fungi.
Answer:
The various products involved are as follows:

  1. Bakery products. Bread and cakes from wheat flour.
  2. Food products. Wines, beers from fruit juices or barley ; idli and dosa from a mixture of powdered rice and dal.
  3. Processed cheese.
  4. Some fungi such as mushrooms are directly used as food products.
  5. Some very important medicines, such as penicillin are made from fungi.
  6. Moulds spoil food, damage potato and crop plants, corn and wheat. They also cause rotting of clothes, shoes and wooden materials.
  7. Some fungi cause diseases like athlete’s foot and ringworm.

Question 11.
How is bread formed ?
Answer:
When yeast together with some sugar and warm water is mixed with flour (atta or maida), the dough begins to rise. The presence of sugar and the warmth stimulates rapid growth of the yeast cells. During their reproduction, yeast cells produce carbon dioxide. Bubbles of CO2 fill the dough and make it rise. When baked into a loaf, the bread becomes light and spongy.

Question 12.
How is the mixture of ground rice and dal made sour ?
Answer:
The mixture of ground rice and dal is allowed to stand for a few hours. It becomes sour. It is the growth of yeast cells that causes the mixture to rise and become sour.

Question 13.
Suggest some methods to prevent the growth of moulds.
Answer:

  1. Keep the things at low temperatures.
  2. Keep the things in clean closed containers.
  3. Keep the things in dry condition in dry storage.
  4. Keep the food in the form of syrups, pickles, in the form of preserved food.
  5. Keep the articles away from the reach of microorganisms present in the air.

Question 14.
Write the importance of fungi in medicines.
Answer:
Antibiotics are obtained from fungi, and Penicillin is obtained from the fungus, Griscofulvin is extracted from the fungus Griscofulvum.

PSEB 8th Class Science Solutions Chapter 2 Microorganisms: Friend and Foe

Question 15.
What are the major differences between algae and fungi ?
Answer:

Algae Fungi
1. Green in colour. 1. Colourless or non-green.
2. Outer cell wall is formed by cellulose. 2. Outer cell is formed of fungus cellulose.
3. Autotrophic. 4. Saprophytic or Parasitic.
4. Aquatic in habitat. 3. Heterotrophic.
5. Grow on wet surfaces. 5. Grow on moist organic surface.

Question 16.
What are vaccines ?
Answer:
Vaccines.
A vaccine consists of antigens of mild strains of pathogens of a specific disease. When injected into the blood stream, it stimulates while blood cells to produce antibodies.

Question 17.
Describe the role of blue green algae in the fertility of soil.
Answer:
Blue green algae play an important role in the fertility of soil due to the following reasons:

  1. They make the nitrogen available to the soil.
  2. They increase the humus content of the soil.
  3. They support the crop growth.
  4. They improve the water holding capacity of the soil.

Question 18.
Describe some of the important landmarks in the study of microorganisms.
Answer:
Important landmarks in the study of microorganisms are as follows:

Name of the scientist Year Contribution
Robert Hooke 1665 Observed cork cells, spermatozoa and bacteria using a simple microscope and named them as tiny animalcules.
Louis Pasteur 1857

1859

 Fermentation is a biochemical process.

Microbes produce only from pre-existing microbes of same species.
Robert Koch 1872 Tubercle bacillus is the main cause of tuberculosis germ theory of disease.
Shikabasaburo

Alexander Fleming

 1889

1929

 Tetanus disease is due to Tetanus bacillus.

Antibiotic penicillin from Penicillium notatum (a fungus).

Question 19.
What is food poisoning ?
Answer:
Food Poisoning. Sometimes the microorganisms grow on our food items and spoil it. When we eat this food, it causes food poisoning. It causes serious illness and even death.

Question 20.
Explain the following terms in brief:
(a) Immunity
(b) Antibodies
(c) Vaccination.
Answer:
(a) Immunity.
Immunity is the ability of a person (or organism) to resist the development of a disease even when infective dose of the pathogen has been introduced. The science of development of resistance or defence to the causative agents of the diseases is termed as immunology. Foundations of immunology were laid by Edward Jenner (1796) who successfully developed first vaccine against small pox.

(b) Antibodies.
It is a substance occurring naturally in the blood or produced in response to the presence of antigen which is able to overcome the toxic effect of an antigen.

(c) Vaccination.
It is a process of injecting a substance (Vaccine) into a healthy person in order to develop immunity against a specific disease.

PSEB 8th Class Science Solutions Chapter 2 Microorganisms: Friend and Foe

Question 21.
Write three ways of entering microorgnisms into the body.
Answer:
Entry of microorganisms into the body

  1. Through the air we inhale.
  2. Through the water we drink, and the food we eat.
  3. Through skin.

Question 22.
What is vaccine ? Describe the importance of vaccination.
Answer:
Vaccine. A vaccine consists of a small amount of dead or weakened germs of a particular disease that are injected into the body. Injecting or swallowing a vaccine is called the vaccination when the vaccine is injected into our body. Our body produces antibodies that fight with those dead or weakened germs. These antibodies stay in our body to prevent the future attack of such kind of microbes. Thus, our body develops immunity against the particular disease for which vaccination is provided.

Question 23.
Write a note on cyanobacterial cell.
Answer:
PSEB 8th Class Science Solutions Chapter 2 Microorganisms Friend and Foe 6
Cyanobacteria.
These are chlorophyll containing autotrophic microscopic bacteria, also called blue green algae. They may be filamentous or colonial in form. Main examples are Oscillatoria, Spirulina, Nostoc, Stigonema.

A typical cyanobacterial cell consists of a four layered cell-wall followed by plasma membrane. The cytoplasm contains gas vacuoles, ribosomes photosynthetic pigments such as chlorophyll a, carotenoids and circular double stranded naked DNA. The reserve food is in the form of cyanophycean starch, liquid globules and cyanophycean protein granules.

Question 24.
What are diatoms ? Sketch a few examples of diatoms.
Answer:
Diatoms.
They are microscopic unicellular algae found in fresh water springs, estuaries and marine water of ocean. They occur mostly as individual cells and some form colonies. Diatoms deposit silicon dioxide in their cell wall. They reproduce asexually as well sexually.
Examples of Diatoms
PSEB 8th Class Science Solutions Chapter 2 Microorganisms Friend and Foe 7

Question 25.
Ajit kneaded 1/2 kg maida along with lukewarm water. He also added some sugar and yeast in it. What will be the effect on kneaded flour after 2 hours ? Give reason for your answer.
PSEB 8th Class Science Solutions Chapter 2 Microorganisms Friend and Foe 8
Answer:
The dough begins to rise. The presence of sugar and yeast stimulates rapid growh of the yeast cells. During their reproduction, yeast cells produce carbon dioxide. Bubbles of CO2 fill the dough and make it rise.

PSEB 8th Class Science Solutions Chapter 2 Microorganisms: Friend and Foe

Long Answer Type Questions

Question 1.
Sketch few of the micro-organisms.
Answer:
PSEB 8th Class Science Solutions Chapter 2 Microorganisms Friend and Foe 9

PSEB 8th Class Science Solutions Chapter 2 Microorganisms Friend and Foe 11

Question 2.
Give in a tabulated form some of the common diseases affecting man and their mode of transmission and methods of prevention.
Answer:
Some Common Human Diseases Caused by Micro-organisms:
PSEB 8th Class Science Solutions Chapter 2 Microorganisms Friend and Foe 12
PSEB 8th Class Science Solutions Chapter 2 Microorganisms Friend and Foe 13

Question 3.
Give some of the common plant diseases caused by micro-organisms.
Answer:
Common Plant Diseases Caused by Micro-organisms

Plant Diseases Micro-organism Mode of Transmission
Citrus canker Bacteria Air
Rust of wheat Fungi Insects and seeds
Yellow vein mosaic of Ladyfinger Virus Insect

Question 4.
What is meant by food preservation? Explain the different methods of food preservation used for foods.
Answer:
Food Preservation. The processes by which the perishable food materials are treated to prevent their spoilage and retain their nutritive value for long periods
is called food preservation.
The substances used for food preservation are called food preservatives.
Different Methods of Food Preservation:

1. Dehydration and Sun Drying.
The process of removal of water from fruits, vegetables is called dehydration. It reduces the moisture content of food materials and, therefore, prevents the food from spoilage. Drying in the sun is one of the oldest methods of food preservation.

2. Preservation by Salt and Sugar.
Common salt and sugar are good preservatives. These stop the bacterial growth in the food material. Pickles, jam, jelly, ketchup, squash, etc. are preserved by adding salt and sugar.

3. Deep Freezing. It is a direct method for the prevention of bacterial growth. In this method, the food materials are cooled below 0 C. Fruits vegetables, meat, fish, etc. can be easily preserved by this method.

4. Chemical Preservation. Certain chemicals can be used to preserve food. The substances which are added to the food materials to prevent their spoilage are called food preservatives. Benzoic acid, Potassium metabisulphite, etc. can be used. Irradiation, canning, and bottling are also used for the preservation of food.

PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation

by

Punjab State Board PSEB 8th Class Social Science Book Solutions Geography Chapter 1 Resources – Types and Conservation Textbook Exercise Questions and Answers.

PSEB Solutions for Class 8 Social Science Geography Chapter 1 Resources – Types and Conservation

SST Guide for Class 8 PSEB Resources – Types and Conservation Textbook Questions and Answers

I. Answer the following questions in 1-15 words :

Question 1.
What do you understand by the term ‘resources’?
Answer:
All the useful elements of the environment which satisfy human needs are called resources. Resources are called ‘Gifts of nature’ such as rocks, minerals, soil, rivers, plants, and animals. These are valuable for mankind. Man’s surroundings provide him with resources.

Question 2.
Which are the Natural Resources and who provides us?
Answer:
Forests, minerals, soil, and solar energy are natural resources. These make our environment or surroundings. These natural surroundings provide rsesources.

Question 3.
List all the types of resources.
Answer:
The three categories of resources are :

  1. Natural Resources
  2. Human Resources
  3. Human Made Resources.

PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation

Question 4.
Define ‘soil’.
Answer:
The loose and unconsolidated material which forms the upper layer of the crust is called soil. Soil is formed by the breaking of parent rock.

Question 5.
What do we get from Seas?
Answer:
The big water bodies are called seas. Seas provide us organic minerals and power resources, fish, pearls, diamonds, etc. At some places, petroleum is also obtained from sea.

Question 6.
How can you conserve the resources properly?
Answer:
The proper and planned use of resources help in the conservation of resources. These should not be misused.These should not be wasted or destroyed.

II. Answer the following questions in 50-60 words :

Question 1.
Differentiate between Biotic and Abiotic resources.
Answer:

Biotic Resources Abiotic Resources
1. These are obtained from living things. 1. These are obtained from non-living things.
2. Plants and animals are its examples. 2. Minerals and rocks are examples.
3. These are found in Biosphere and provide food, energy (coal and petroleum) and raw materials. 3. These are found on lithosphere and provide raw materials for industries.

Land: Land is the basis of human activities. It helps in agriculture, setting up of industries, means of transportation, sports, tourism, etc. Houses are built on land.Question 2.
Write a short note on the importance of Land and Soil Resources.
Answer:
The following is the importance of Land and Soil :

  1. Soil: Man grows crops on soils. It provides food and other raw materials to man. Fertile soils support dense population.

Question 3.
From where do we get the minerals and where they used?
Answer:
Minerals are obtained from the interior of earth from rocks. These are metallic and non-metallic. Metallic minerals include iron, copper, gold, silver, aluminium. Non- metallic minerals include coal, mica, manganese and oil. These are used in industries. Before use, these are smelted to make pure.

PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation

Question 4.
Explain the Developed and Potential resources with examples.
Answer:

Potential Resources

Developed Resources
1. These are total quantity of a resource found existing in nature. 1. These are only those resources, which have been judged good for use.
2. These have not been put to use. 2. They are put to use fully for economic gain.
3. These are found everywhere. 3. These are not found everywhere.
4. Africa has 40% potential water power resources of world due to large rivers. 4. Africa has only 1% of developed water power resources of world due to lack of technology.

Question 5.
Why should we use the exhaustible resources wisely and with hesitation?
Answer:
The modern civilisation depends upon products—natural as well as man made. With the help of technology, resources are being utilised on a large scale. The exhaustible resources will not last long. 80% of the fossil fuels will be finished in one century With the exhaustion of resources, the civilisation will come to an end. Therefore conservation of resources is necessary. A balance should be maintained between population growth and utilisation of resources so that the continuity of modern civilisation goes on. The natural resources are common heritage. We have to share these with future generations.

Question 6.
What is the contribution of human resources to the development of other resources ?
Answer:
Resources are the elements of Bio-physical environment. But these become resources only when humans preserve these. Coal was always there, but it became a resource only when man used it as a source of energy. So it has been rightly said that the resources are not, they become so. Man uses technology and skill to develop resources. Machines and tools are used. Japan is a very good example where in spite of non existence of resources, the country has progressed to a great extent.

III. Answer the following questions in about 125-130 words :

Question 1.
What do you understand by the resources ? Name their types and explain their importance and methods of conservation.
Answer:
Type of Resources: Resources are generally classified into three types :

  1. natural
  2. human and
  3. human-made.

Natural or man-made resources are of various types. On the bases of life, existence, availability, level of development and utilization these resources can be divided into the following types :

  • Biotic and Abiotic Resources
  • Developed and Potential Resources
  • Exhaustible and Inexhaustible Resources
  • Soil and Land Resources
  • Marine-and Mineral Resources
  • Human Resources

PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation 3
Resource Types

1. Biotic and Abiotic Resources. Biotic resources are those basic resources which originate from the living things. Approximately 85% of the world’s total food depend upon these biotic resources. Plants and other living creatures are included in these types of resources. These resources provide raw material for our industries. Coal and petroleum are also included in the category of biotic resources as they are produced from the plants and animals.
The non-living products like minerals, water etc., which are provided by the nature are called ‘Abiotic Resources’. The minerals are the base of our industry. If we do not use the minerals with care, these will exhaust very soon.

2. Developed and Potential Resources. The resources which are used for some economic gain are termed as ‘Developed resources’. On the other hand, the resources which are available but are not being used or can be used in the future are called ‘Potential Resources’. The rivers descending the mountains can be used to produce electricity and are included in the category of potential resources. When the water of these rivers is used to produce electricity then this water is known as a developed resources. The coal lying underneath the earth is a potential resource whereas the coal which is being used is considered as a developed resource.

3. Exhaustible and Inexhaustible Resources. The resources which are being depleted very fast .because of their continuous and excess use are called exhaustible resources, as petroleum products are being used very fast. The time is not very far away when there will be shortage or non-existence of these resources. Therefore, the exhaustible resources should be used wisely and carefully. ‘

The resources which get renewed as we use them are called inexhaustible resources. For example : We are using sun energy, wind energy, water and forests but these resources do not get depleted rather get renewed. These types resources are being made available continuously. ‘

4. Soil and Land Resources. Soil is a small and uppermost layer of the earth which is formed by breaking of parent rock, due to climate effect and decomposition of plants and animals. Soil is a very important resource for man. It plays an important role in the growth of plants and crops. The soils are of different types like sandy soil, clayey soil, loamy soil, alluvial soil, mountain soil, red soil, black soil etc. Man gives preference to fertile soil for growing crops. The areas with fertile soil are densely populated and are full of economic activities.
Land means the earth’s surface where man carries on his economic or other activities. Man had been using the land resource for a very long time. The land resource is being used for the purpose of agriculture, industry, to develop means of transport, sports, tourism etc. Man uses the land, keeping in view its relief, slope, type of soil, drainage or his requirements.

5. Marine and Mineral Resources Marine Resources. Water is a basic and a very important resource for man. Approximately 71% part of the earth is water. Big water bodies are called ‘seas’. These water bodies provide many biotic, mineral and energy resources. It is believed that the life on the earth started from the seas and oceans. 75% of the total land creatures originated from the water bodies. We get fish, pearls, shells, diamonds etc. from the seas in large quantities. At some places we get petroleum substances from the sea coasts. The fish provide food to the large part of the World’s population.

Mineral Resources: Mineral resources are the substances which are taken from the earth. Basically these are of two types-Metallic and non-metallic minerals. Metallic minerals include iron, copper, silver, gold, aluminium etc.

Petroleum, coal, mica, manganese etc. are some of the non-metallic minerals. The minerals are taken from different types of rocks. The minerals are the bases for our industries, therefore, much significance is attached to them.

6. Human Resources: Man has been awarded the best status of all the creatures produced by the nature. With his intelligence and ability to work, man himself is a very huge resource. Man’s capability plays an important role in the use of all other resources. The development of human resources is reflected from the development of any area. Japan is a very good example where inspite of the deficiency or non-existence of resources, the country has progressed to a great extent. The development of all other resources is incomplete till the human resource is fully developed. Man’s qualities, capacity, educational and technical qualification etc. play an important role in the development.

PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation

IV. Activity

Question 1.
Make a list of Hydroelectricity producing dams related to Punjab. Note down the names of rivers on which these dams are situated and names of districts in which these dams have been constructed.
Answer:

Dams

 Rivers

Districts
1. Bhakra Sutlej Himachal Pradesh
2. Ganguwal Nangal Hydel Channel Ropar
3. Kotla Nangal Hydel Channel Ropar
4. Pong Dam Beas Hoshiarpur
5. Thein Daam Ravi Gurdaspur
6. Mukerian Beas Hoshiarpur

PSEB 8th Class Social Science Guide Resources – Types and Conservation Important Questions and Answers

I. Multiple Choice Questions :

Question 1.
Which are the biotic resources?
(a) rocks
(b) minerals
(c) plants
(d) hills
Answer:
(c) plants.

Question 2.
What are the basis of classifying resources?
(a) life
(b) achievement
(c) use
(d) all of the above.
Answer:
(d) all of the above.

PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation

Question 3.
Which is not termed of human resource?
(a) knowledge
(b) efficiency
(c) intelligence
(d) transparency.
Answer:
(d) transparency.

Question 4.
Which of the following are the ubiquitous resource?
(a) air, water
(b) coal, copper
(c) iron, ore
(d) uranium.
Answer:
(a) air, water.

Question 5.
Nager coil is famous for __________
(a) coal mining
(b) windmills
(c) solar energy
(d) oil refinery.
Answer:
(b) windmills.

Question 6.
In this picture some resources are shown these resources are :
PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation 1
(a) Abiotic resources
(b) Biotic resources
(c) Ubiquitous resources
(d) Human resources.
Answer:
(b) Biotic resources.

Question 7.
We enjoy a lot the beauty of waterfalls mountains, sea etc. Thus, they are natural resources which have ______value.
(a) Ethical Value
(b) Artistic Value
(c) Aesthetic Value
(d) Economic Value.
Answer:
(c) Aesthetic Value.

PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation

Question 8.
The following picture shows a specific type of plant. Identify the name of this plant :
PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation 2
(a) Thermal Plant
(b) Nuclear Plant
(c) Biogas Plant
(d) Hydro electric plant
Answer:
(c) Biogas Plant.

Fill in the Blanks :

Question 1.
_______ resources are derived from living things.
Answer:
Biotic

Question 2.
Localised resources are found only in _______ place.
Answer:
certain

Question 3.
The example of human resource is _______
Answer:
people

Question 4.
Anything that satisfy human needs is called _______
Answer:
resource

Question 5.
Non living resources are called _______ resources.
Answer:
Abiotic.

True/False :

Question 1.
Solar and wind energy is an example of renewable resources.
Answer:
True

Question 2.
Environment means set of surroundings.
Answer:
True

Question 3.
Resources are generally classified into two types.
Answer:
False.

PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation

Question 4.
Land use depend upon relief, slope, soil etc.
Answer:
True

Question 5.
Coal and petroleum are not biotic resource.
Answer:
False.

Very Short Answer Type Questions

Question 1.
How does something become a resource?
Answer:
That thing which has a value and utility become a resource.

Question 2.
Why is modern man dependent on resources?
Answer:
In early times, human needs were limited. But now-a-days the needs have increased. So man has to depend upon many resources.

Question 3.
Explain, with examples, that the proper use of resources is real development of resources.
Answer:
Before the invention of coal, petroleum, and aeroplane, man was not aware of the Aluminium. Due to utility of Aluminium, its use increased. So we can say that proper use has led to the development of resources.

Question 4.
What are the four basis of classifying resources?
Answer:

  1. life
  2. achievement
  3. stage of development
  4. use.

Question 5.
Which resources are most important to obtain food-resources?
Answer:
To get food resources, agriculture is the most important source as it provides 85% of food resources.

Question 6.
Why coal and petroleum are biotic resources?
Answer:
Coal and petroleum are formed by organic and living plants and animals. So these are grouped as biotic resources.

Question 7.
How can you assess a country as a rich country?
Answer:
The wealth of a country is measured by its resources. The more developed resources make a country richer.

Question 8.
Why are fertile soil areas densely populated with large economic activities?
Answer:
Fertile soils help in growing crops. In fertile soils agriculture is developed. It leads to dense population and many economic activities.

Question 9.
On what factors does the landuse depend?
Answer:
Landuse depends upon relief, slope, soils, drainage and human needs.

Question 10.
What is human resource?
Answer:
Man made resources include machinery, transportation, industries. Human intelligence, knowledge and efficiency is termed as human resource.

Question 11.
Concept of Resource is changing. Why?
Answer:
The concept of resource is changing. It may expand or contract with the development of knowledge and technology.

Question 12.
Name the important types of soil.
Answer:
Sandy soil, Clayey soil, Loamy soil, Alluvial soil, Red soil, Black soil.

PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation

Question 13.
Classify resources on the basis of their source of origin.
Answer:
Based on their origin, resources can be biotic or abiotic. For example plants, animals, rocks, minerals, soils etc.

Question 14.
How can we conserve the resources?
Answer:
We can conserve resources by reducing consumption, recycling and reusing things.

Question 15.
What is technology?
Answer:
Technology is human made resource. It is the application of latest knowledge and skill in doing or making things.

Question 16.
The population of India is lesser than only one country. Name that country.
Answer:
China.

Short Answer Type Questions

Question 1.
What is a resource?
Answer:
All the useful elements of environment which satisfy the human needs are called resources. Resources are called ‘Gifts of nature’ such as soils, rivers, plants, animals, rocks and minerals. These are valuable for mankind.

Question 2.
Why are humans also called a resource?
Answer:
They are called a resource because by developing the human skills only the resources can be developed. Resources are not, but they become due to man.

PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation

Question 3.
What do you understand by the statement “natural resources have utility and value”?
Answer:
Natural resources have utility and value is true. All the materials that are available in nature have some use or value and that’s what makes them valuable.

  1. Water, air vegetation all have utility or usability, they may or may not have economic value.
  2. Metals have economic value but a landscape may not have; but both are important to satisfy human need.
  3. Time and technology makes them a resource.

Question 4.
What leads to creation of new resources?
Answer:
The knowledge, ideas, inventions and discoveries by people leads to creation of more resources. The discovery of fire led to idea of cooking and other related processes. Invention of wheels led to changes in modes of transport.

Question 5.
Discuss the role of technology in the utilisation of resources.
Answer:
Technology helps to develop the means of production. It increases the value of natural resources. Technology depends upon the human skill and technical knowledge. Mechanism helps in the better utilisation of natural resources. A resource is no resource until it is used.

Question 6.
Distinguish between Natural Resources and Human-made Resources.
Answer:

Natural Resources

Human made Resources
1. They are free gifts of nature. 1. They are not free gifts of nature.
2. They are both renewable and non-renewable. 2. They are non-renewable.
3. They help in the economic development of the country. 3. They help in economic and social development.

Question 7.
Distinguish between Exhaustible and Inexhaustible Resources.
Answer:

Exhaustible Resources

Inexhaustible Resources
1. These resources get exhausted after use. 1. These resources do not get exhausted after use.
2. These resources are regenerated after a very long time. 2. These are renewable or flow resources.
3. Minerals and metals are exhaustible resources. 3. Forests, water power are inexhaustible resources.

Question 8.
What do we mean by a reserve?
Answer:
It refers to that portion of resource which<can be developed profitably with the help of available technology.
For example : High quality iron is used for steel making. But sometimes a low grade iron ore or coal (lignite—Less than 40% carbon content) is used for steel making. Lignite coal in Neyvelli (Tamilnadu) is an example of a reserve resource.

Question 9.
What is meant by human-made resources?
Answer:
They are those resources which are created by human being with the help of machines. Some of the examples are buildings, tools etc.

Question 10.
Give two examples of human made resources.
Answer:
The human made resources are those resources which are created by human beings.

Some examples are :

  1. Buildings,
  2. Machines.

PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation

Question 11.
Give an account of natural resources.
Answer:
Natural Resources:
Resouces drawn from (nature) and used without much modification are called natural resources.

  • Water, soils, minerals are all natural resources.
  • Many of the resources are free gift of nature.
  • They can be used directly.
  • In some cases tools and technology are needed to use a natural resource in the best way.

Question 12.
How are natural resources classified?
Answer:
Natural resources are classified into different groups :

  • Level of development and use
  • origin
  • stock
  • distribution.

Question 13.
Why natural resources are important?
Answer:

  • These are important for the economic development of a region or a country.
  • They are the main sources of our agricultural activities.
  • They provide raw materials for the industry.
  • All activities depend on them directly or indirectly.
  • They help in maintaining the ecological balance of nature. Thus they should be used carefully.

Question 14.
What is meant by conservation?
Answer:
It means the use of the natural resources carefully without any wastage. They are important to us, so they should be used wisely so that they are not exhausted and we may have to face their scarcity.

PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation

Question 15.
‘Resources are not resources, they become so.’ Explain.
Answer:
Resources are elements of Bio-physical environment. But these become resources only when humans preserve these. Coal was always there, but it became a resource only when man used it as a source of energy. So it has been rightly said that resources are not resources, they become so.

Question 16.
What are the ill effects of overuse of resdUrces? What are the measures to make the earth habitate? ”
Answer:
Ill effects :
Degradation of resources: The rising demand for various resources has caused degradation or depletion of many valuable resources.

Example :

  • Overuse of soil has caused infertility in many areas.
  • Similarly widespread deforestation and killing of birds and animals have endangered many plants and animal species.
  • The quality of air, water and land resources has also been affected badly due to misuse or overuse of resources.

Question 17.
Distinguish between Renewable and Non-renewable resources.
Answer:

Renewable Resources

Non-renewable Resources
1. These have the capacity to regenerate. 1. These cannot regenerate that quickly.
2. These are free gifts of nature. 2. These are not free gifts of nature.
3. These are those resources which can be used again. 3. These cannot be used again.
4. For example air, water, etc. 4. For example coal, natural oil.

Question 18.
Future of our planet is linked with life support system. Discuss.
Answer:
Our earth is the only planet where life has been found till today. Future of our planet and its people, is linked with our ability to maintain and preserve the life support system that nature provides. This makes it our duty to ensure that the natural environment is preserved and properly managed.

Question 19.
What is sustainable development?
Answer:
By sustainable development, we mean that resources are utilised carefully so that besides meeting the present requirement it also takes care of the future generations.

Question 20.
What is our duty regarding resources?
Answer:
It is our duty to ensure that

  • The diversity of life on the earth is conserved.
  • All uses of renewable resources are sustainable.
  • The damage to natural environment system is minimised.

PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation

Question 21.
Distinguish between Natural Resources and Human Resources.
Answer:

Natural Resources

Human Resources
1. They are free gifts of nature. 1. They are not free gifts of nature.
2. They are both renewable and non renewable. 2. They are non renewable.
3. They help in the economic development of the country. 3. They help in the economic and social development.

Question 22.
In how many ways man uses his environment?
Answer:
Environment means set of surroundings. It provides many resources to get food, shelter and clothing. Man uses land for crops, houses, factories,- construction of transport network. Man uses minerals for industries. He uses forests for timber, herbs and shrubs. Man gets fish and other benefits from seas and oceans.

Question 23.
How are development and resources interdependent?
Answer:
Development is possible through resources. Resources are the foundations of development. These have economic significance for human beings. Land, water and air are basic requirements for agriculture. We can’t do agriculture without these resources. Minerals are basic requirement for industries. Industries cannot run without minerals. Thus development and resources are inter-dependent.

Question 24.
Distinguish between actual resources and reserve resources.
Answer:
Actual Resources. Actual resources depend upon physical conditions of environment. These are surveyed. Their quantity is determined and are actually used. Their quantity is known.

Reserve resources are a part of actual resources. These can be made useful with technology. A low grade coal-lignite is a reserved resource in some areas.

PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation

Question 25.
Give one example each of developed and potential resources.
Answer:
When the water of river is used to produce electricity, it is called a developed resource. The coal underlying the earth is a potential resource.

Fill in the blanks :

Question 1.
_______ resources are derived from living things.
Answer:
Biotic

Question 2.
Localised resources are found only in places.
Answer:
certain

Question 3.
The example of human resource is _______
Answer:
people

Question 4.
Solar and wind energy is an example of _______
Answer:
Renewable resources

Question 5.
Anything that is used to satisfy a need is called a _______
Answers :
resource

PSEB 8th Class Social Science Solutions Chapter 1 Resources – Types and Conservation

Question 6.
Petroleum in _______ is an example of actual resource.
Answer:
West Asia

Question 7.
_______ is the application of latest knowledge and skill is doing or making things.
Answer:
Technology.

Long Answer Type Questions

Question 1.
Write a detailed note on the conservation of resources with special reference to marine and mineral resources.
Answer:
Conservation of Resources. Man depends upon his environment to meet his needs. He uses water, land, soil, vegetation, etc. to satisfy his needs. Man is using these resources at such an alarming rate that there will be a serious shortage of these resources in the near future. Natural resources are of a very limited supply. So conservation of resources is essential for the survival of man.

To some people, conservation means that the available resources should not be used. These should be held back. But conservation of resources means a careful and rational utilization of resources. These resources should be used intelligently for the welfare of mankind. It means careful control and management of resources so that these may be used for the benefit of future generations also. These should be preserved from reckless exploitation and wanton destruction. These resources should not be wasted in a short time. The resources should be maintained in a healthy condition for their use so as to achieve a high standard of living for mankind.

Importance:
Conservation of all resources has an economic, scientific, and aesthetic value for mankind :

  • Conservation of resources is necessary as these are the basis of the economic activities of man.
  • Resources must be conserved to meet the different human needs.
  • Conservation of resources is essential as life depends on these useful elements of the environment such as air, water, soil, rocks, forests, and water bodies.
  • Many areas of the world are still under-developed because the resources of these areas have not been used in a planned and rational manner.

PSEB 8th Class Science Solutions Chapter 5 Coal and Petroleum

by

Punjab State Board PSEB 8th Class Science Book Solutions Chapter 5 Coal and Petroleum Textbook Exercise Questions and Answers.

PSEB Solutions for Class 8 Science Chapter 5 Coal and Petroleum

PSEB 8th Class Science Guide Coal and Petroleum Textbook Questions and Answers

Exercises

Question 1.
What are the advantages of using CNG and LPG as fuels?
Answer:
Advantages of LPG:

LPG is considered to be a better fuel because of the following reasons:

  1. LPG has a high calorific value. Its calorific value is about 50 kJ/g. This means that when 1 gram of LPG burns in a gas stove, it produces about 50 kilo-joules of heat energy.
  2. It burns with a smokeless flame and so does not cause pollution.
  3. LPG does not produce any poisonous gases on burning.
  4. LPG is easy to handle and convenient to store.
  5. It undergoes complete combustion.
  6. LPG is a very neat and clean domestic fuel.

Advantage of CNG:
It does not cause air pollution.

Question 2.
Name the petroleum product used for surfacing of roads.
Answer:
Bitumen.

PSEB 8th Class Science Solutions Chapter 5 Coal and Petroleum

Question 3.
Describe how coal is formed from dead vegetation. What is this process called ?
Answer:
Formation of coal from dead vegetation:
About 300 million years ago, the forests got buried under the soil. They were compressed by soil deposits and temperature also rose as they sank deeper and deeper. Due to this high temperature and pressure coal was formed from dead vegetation by process of carbonisation.

Question 4.
Fill in the blanks.
(a) Fossil fuels are …………….. , …………… and ……………
(b) Process of separation of different constituents from petroleum is called ………………… .
(c) Least polluting fuel for vehicle is ………………..
Answer:
(a) Coal, petroleum, natural gas.
(b) refining.
(c) CNG (Compressed natural gas).

Question 5.
Tick True/False against the following statements.
(a) Fossil fuels can be made in the laboratory.
Answer:
False

(b) CNG is more polluting fuel than petrol.
Answer:
False

(c) Coke is almost pure form of carbon.
Answer:
True

(d) Coal tar is a mixture of various substances.
Answer:
True

(e) Kerosene is not a fossil fuel.
Answer:
True

Question 6.
Explain why fossil fuels are exhaustible natural resources.
Answer:
Fossil fuels are formed from remains of dead organisms and it took million of years to get these organisms converted into fuels. The known reserves of these fuels are limited and so, these are exhaustible fuels.

Question 7.
Describe the characteristics and uses of coke.
Answer:
Characteristics of Coke:

  1. It is tough, porous and black substance.
  2. It is pure form of carbon.

Uses of Coke:

  1. It is used to manufacture artificial graphite.
  2. It is used in manufacture of calcium carbide required for manufacture of acetylene gas. Acetylene gas is the basic raw material for manufacture of acetic acid and P.V.C.
  3. It is used in manufacture of water gas and producer gas used as an important fuel.
    • Water gas is not single gas. It is a mixture of equal volumes of carbon monoxide and hydrogen.
    • Producer gas is produced by passing controlled amount of air over red hot coke. Producer gas is in fact a mixture of one part of carbon monoxide and two parts of nitrogen by volume.
  4. It is used to extract metals like copper, iron, zinc, lead, tin etc., from their ores.
  5. Since coke does not produce any smoke, hence it is used as a household fuel.

Question 8.
Explain the process of the formation of petroleum.
Answer:
Formation of Petroleum.
Petroleum is formed from the bacterial decomposition of the remains of animals and plants which got buried under the sea millions of years ago. When these organisms died, they sank to the bottom and got covered by sand and clay. Over a period of millions of years, these remains got converted into petroleum oil by heat, pressure and catalytic action. The hydrocarbons formed rose through porous rocks until they were trapped by impervious rocks forming an oil trap. Natural gas is found above the surface of petroleum oil.

PSEB 8th Class Science Solutions Chapter 5 Coal and Petroleum

Question 9.
The following table shows the total power shortage in India from 1991-1997. Show the data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the year on the X-axis.

S. No. Year Shortage %
1 1991 7.9
2 1992 7.8
3 1993 8.3
4 1994 7.4
5 1995 7.1
6 1996 9.2
7 1997 11.5

Answer:
PSEB 8th Class Science Solutions Chapter 5 Coal and Petroleum 1

PSEB Solutions for Class 8 Science Coal and Petroleum Important Questions and Answers

Multiple Choice Questions

Question 1.
Gurmeet’s mother uses cylinder to cook chapatti on gas burner at home. Name the gas in cylinder.
(a) Air
(b) Oxygen
(c) L.P.G.
(d) C.N.G.
Answer:
(c) L.P.G.

Question 2.
Monika read in a newspaper that a man became unconscious because of burning coal in a closed room. The teacher told her that during burning coal, a gas is produced which causes death of a person. Name
this gas.
(a) Oxygen
(b) Nitrogen
(c) Carbon-monoxide
(d) Hydrogen.
Answer:
(c) Carbon-monoxide.

Question 3.
The example of fossil fuel is:
(a) Air
(b) Sunlight
(c) Water
(d) Coal
Answer:
(d) Coal

Question 4.
Which out of the following is used as fuel in households ?
(a) Diesel
(b) Petrol
(c) Kerosene oil
(d) Bitumen.
Answer:
(c) Kerosene oil.

Question 5.
The purest form of carbon is:
(a) Coaltar
(b) Coal gas
(c) Diamond
(d) None of the above.
Answer:
(c) Diamond.

Question 6.
Which out of the following is the least pollution causing fuel ?
(a) Petrol
(b) Coal
(c) Kerosene oil
(d) C.N.G.
Answer:
(d) C.N.G.

PSEB 8th Class Science Solutions Chapter 5 Coal and Petroleum

Question 7.
Which is the natural solid fuel ?
(a) Coal
(b) Coke
(c) L.P.G.
(d) Coal tar
Answer:
(a) Coal.

Question 8.
Which among the following is the best domestic fuel ?
(a) Petrol
(b) Coal
(c) Kerosene oil
(d) C.N.G.
Answer:
(d) C.N.G.

Question 9.
Which of the following is the fossil fuel ?
(a) Air
(b) Hydrogen gas
(c) Water
(d) Coal.
Answer:
(d) Coal.

Question 10.
Which out of the following is the non renewable source of energy ?
(a) Air
(b) Sunlight
(c) Coal
(d) Forests
Answer:
(c) Coal

Question 11.
Which out of the following is called black gold ?
(a) Diesel
(b) Coal
(c) Bitumen
(d) Petroleum.
Answer:
(d) Petroleum.

Question 12.
Which out of the following is limited natural resource ?
(a) Air
(b) Sunlight
(c) Natural gas
(d) None of the above.
Answer:
(c) Natural gas.

Very Short Answer Type Questions

Question 1.
Name some natural materials.
Answer:
Air, water, soil, forests, minerals etc.

PSEB 8th Class Science Solutions Chapter 5 Coal and Petroleum

Question 2.
Name some man-made materials.
Answer:
Glass, cement, clothes, houses etc.

Question 3.
Define the term fossil fuel. Name three fossil fuels.
Answer:
Fossil fuels.
These are the fuels which are formed in nature from the dead remains of organisms over millions of years ago.
Examples. Coal, natural gas, petroleum etc.

Question 4.
How is coke prepared ?
Answer:
Coke is prepared by the destructive distillation of coal. The gases, and other substances present in coal are given off on heating. The black residue left behind is coke.

Question 5.
Name two products formed by Destructive distillation of Coal.
Answer:

  1. Coal gas
  2. Coal tar.

Question 6.
Name some products formed as a result of Fractional distillation of Petroleum.
Answer:
Asphalt, petrol, diesel oil, paraffin wax, fuel oil, kerosene oil.

Question 7.
Name three products of petroleum.
Answer:
Fertilizer, Insecticide, Artificial rubber.

Question 8.
What will happen if fossil fuels are used up at a fast rate ? Give reasons.
Answer:
Fossil fuel will get exhausted because the earth cannot recreate them rapidly.

PSEB 8th Class Science Solutions Chapter 5 Coal and Petroleum

Question 9.
Coal, petroleum, natural gas are example of which type of fuel ?
Answer:
Fossil fuel.

Question 10.
What is petroleum ?
Answer:
Petroleum. Petroleum is thick viscous crude oil with an unpleasant odour.

Question 11.
Which type of rocks store petroleum in them ?
Answer:
Impervious (non-porous) rocks.

Question 12.
Which process is used for refining petroleum ?
Answer:
Fractional distillation.

Question 13.
How is petroleum gas produced ?
Answer:
It is produced in the form of uncondensed gas during fractional distillation of crude petroleum oil.

Question 14.
What is the use of bitumen ?
Answer:
Road surfacing.

Question 15.
Which liquid fuel is used in stoves, lamps and jet air-crafts ?
Answer:
Kerosene oil.

Question 16.
Which product of petroleum is used for dry cleaning ?
Answer:
Petrol.

PSEB 8th Class Science Solutions Chapter 5 Coal and Petroleum

Question 17.
Name few exhaustible natural resources.
Answer:
Forests, wild life, minerals, coal etc.

Question 18.
Give examples of in-exhaustible natural resources.
Answer:
Air, water, sunlight etc.

Question 19.
Which natural material is available at a blacksmith’s place ?
Answer:
Coal.

Question 20.
What is main component of coal ?
Answer:
Carbon.

Question 21.
Which process converts dead vegetation into coal ?
Answer:
Carbonisation.

Question 22.
What happens when coal is heated or burn in air ?
Answer:
Carbondioxide gas is released.

Question 23.
Which condition is necessary for destructive distillation ?
Answer:
Absence of oxygen.

Question 24.
What is the latest use of coal-gas ?
Answer:
As a source of heat energy.

PSEB 8th Class Science Solutions Chapter 5 Coal and Petroleum

Question 25.
What is destructive distillation ?
Answer:
Destructive Distillation – The process of heating coal in the absence or limited supply of air is called destructive distillation.

Question 26.
What are hydrocarbons ?
Answer:
Hydrocarbons. The compounds of carbon and hydrogen are called Hydrocarbons.

Question 27.
What are Petrochemicals ?
Answer:
Petrochemicals.
These are the substances obtained from Petrol and Natural gas. These are largely used for the manufacture of detergents, synthetic fibres and plastics etc.

Short Answer Type Questions

Question 1.
Write two differences between Exhaustible and In-exhaustible Resources.
Answer:
Differences between Exhaustible and In-exhaustible Natural Resources.

Exhaustible Natural Resources In-exhaustible Natural Resources
1. Limited quantity in nature. 1. Limitless or unlimited quantity in nature.
2. Gets exhausted on consumption.

Examples: Forests, wild life.

 2. Cannot exhaust on consumption i.e. can be retrieved back.

Examples: Air, Sun energy.

Question 2.
Where is petroleum found in India ?
Answer:
In India, petroleum is found in the states of Gujarat and Assam. It is also obtained from reservoirs buried deep under the sea bed near Mumbai. This oil-bearing region is called Bombay-High. Recently, oil has also been discovered in Godavari and Kaveri basins.

Question 3.
What are the major products of Petroleum refining ?
Answer:
During refining of petroleum following fractions are produced:

  1. Natural gas, Petrol,
  2. Naphtha,
  3. Kerosene oil,
  4. Gas oil (diesel),
  5. Lubricating oil/waxes,
  6. Fuel oil and
  7. Bitumen.

Question 4.
What are the products of coal ?
Answer:
Coal on heating in the absence of air gives coal gas, coal tar, and coke. Coal gas is also a good fuel. Coal tar gives important chemicals such as benzene, toluene, naphthalene, anthracene etc.

PSEB 8th Class Science Solutions Chapter 5 Coal and Petroleum

Question 5.
What is coal gas ? How is it formed ? Give its uses.
Answer:
Coal Gas. Coal gas is a mixture of methane, hydrogen and carbon monoxide.
When coal is heated in the absence of air, coal gas is formed.
Uses.

  1. It is used as a fuel.
  2. It is used for providing reducing atmosphere in metallurgical operations.

Question 6.
Give few uses of coal.
Answer:
Uses of Coal:

  1. As a fuel to cook food.
  2. To produce steam to run an engine.
  3. To produce electricity in Thermal Power plants.
  4. As a fuel in industry.

Question 7.
What is coal tar ? What are its uses ?
Answer:
Coal Tar. Coal tar is a black thick liquid with unpleasant smell. It is a mixture of about 200 substances, which are used as starting materials for the manufacturing of various daily need ithins such as paints, dyes, plastics, films, perfumes, explosives, drugs etc.
Coal tar is also used for road surfacing.

Question 8.
Name at least three constituents of petroleum and give their uses.
Answer:
Constituents of Petroleum

  1. Petrol
  2. Paraffin wax
  3. Diesel.

Uses of Petroleum:

  1. Petrol is used as a motor fuel and aviation fuel. It is also used for dry cleaning.
  2. Paraffin wax is used for making ointments, candles, vaseline etc.
  3. Diesel is used as a fuel for heavy motor vehicles and electric generators.

Question 9.
Define natural resource.
Answer:
Natural Resource. The resource that is obtained from nature is called natural resource.

Question 10.
What are the characteristics of a good fuel ?
Answer:
Characteristics of Good Fuel:

  1. It should be easily available.
  2. It should be cheap.
  3. It should be clean and should not produce poisonous gases and ash after burning.
  4. It should produce more energy.
  5. It should be easy to transport and store.

PSEB 8th Class Science Solutions Chapter 5 Coal and Petroleum

Question 11.
What is the difference between coal and coke ?
Answer:
Differences between Coal and Coke

Coal Coke
1. It is a non-crystalline form of carbon 1. It is an amorphous form of carbon.
2. It is obtained bj? death and decay of plants which remain buried under the earth for years together. 2. It is obtained by heating soft coal in the absence or limited siuply of air.

Long Answer Type Questions

Question 1.
What are fossil fuels ? How are they formed ? Why are they called non¬renewable sources of energy ?
Answer:
Petroleum, natural gas, coal etc., are main forms of fossil fuels. Millions of years ago, remains of animals, plants got buried under the earth before dinosaurs. These remains are called fossils. They remained inside the earth under huge pressure and high temperature in the absence of oxygen, these remains got converted into fossil fuel.

Fossils as a source of non-renewable source of energy.
Fossils were formed several hundred years ago under the earth. Man uses these for his various activities. These cannot be regained after use. So they are called non-renewable source of energy.

Question 2.
Describe the formation of
(a) Coal
(b) Petroleum.
Answer:
(a) Coal Formation.
Coal is believed to be formed from fossils which got buried inside the earth during earthquakes, volcanic eruptions etc., which occurred about 300 million years ago. These fossils were covered with sand, clay and water. In the absence of air and under high temperature and high pressure inside the earth, the fossils got converted into coal. This process of conversion of plants and animals buried inside the earth under high temperature and pressure to coal is called carbonisation. It is a very slow process and may have taken thousands of years.

(b) Formation of Petroleum.
It is believed that petroleum was formed and preserved in its crude state in the earth from the remains of dead microscopic marine plants (phytoplankton) which settled in muddy sediments at the bottom of sea millions of years ago. Prolonged sedimentation and cooking of these organic debris under pressure in the presence of natural catalysts, converted them into petroleum . For this reason, petroleum is also called fossil fuel.
PSEB 8th Class Science Solutions Chapter 5 Coal and Petroleum 2

Question 3.
What is petroleum? How does it occur? How is it mined?
Answer:
Petroleum.
It is dark coloured viscous, foul-smelling, oily liquid. It is a complex mixture of several solid, liquid, and gaseous hydrocarbons mixed with water, salt, and earth particles.

Occurrence of Petroleum.
Petroleum occurs deep down under the earth between two impervious rocks (non-porous rocks) as shown in Fig. Natural gas occurs above the petroleum oil trapped under rocks.

The crude petroleum is obtained by drilling a hole into the earth’s crust and sinking pipes into it. When the pipe reaches the oil deposit, natural gas comes out with great pressure. After the pressure has subsided, the crude oil is pumped out of the oil well. This process of obtaining crude oil from its sources is called mining.

PSEB 8th Class Science Solutions Chapter 4 Materials: Metals and Non-Metals

by

Punjab State Board PSEB 8th Class Science Book Solutions Chapter 4 Materials: Metals and Non-Metals Textbook Exercise Questions and Answers.

PSEB Solutions for Class 8 Science Chapter 4 Materials: Metals and Non-Metals

PSEB 8th Class Science Guide Materials: Metals and Non-Metals Textbook Questions and Answers

Exercises

Question 1.
Which of the following can be beaten into thin sheets?
(a) Zinc
(b) Phosphorus
(c) Sulphur
(d) Oxygen.
Answer:
(a) Zinc.

Question 2.
Which of the following statements is correct?
(а) All metals are ductile.
(b) All non-metals are ductile.
(c) Generally, metals are ductile.
(d) Some non-metals are ductile.
Answer:
(a) All metals are ductile.

PSEB 8th Class Science Solutions Chapter 4 Materials: Metals and Non-Metals

Question 3.
Fill in the blanks.
(a) Phosphorus is very ……………… non-metal.
(b) Metals are …………. conductor of heat and ……………… .
(c) Iron is ……………… reactive than copper.
(d) Metals react with acids to produce ……………………. gas.
Answer:
(a) reactive.
(b) good, electricity.
(c) more.
(d) Hydrogen.

Question 4.
Mark ‘T’ if the statement is true and ‘F’ if it is false.
(а) Generally, non-metals react with acids.
(b) Sodium is a very reactive metal.
(c) Copper displaces zinc from zinc sulphate solution.
(d) Coal can be drawn into wires.
Answer:
(a) True
(b) True
(c) False
(d) False

Question 5.
Some properties are listed in the following Table. Distinguish between metals and non-metals on the basis of these properties. (From Board M.Q.P.)

Properties Metals Non-metals
1. Appearance
2. Hardness
3. Malleability
4. Ductility
5. Heat Conduction
6. Conduction of electricity

Answer:
Differences between metals and non-metals.

Properties Metals Non-metals
1. Appearance Silvery or grey in colour. Different coloured non-metals.
2. Hardness Solid at room temperature. Solid, liquid or gas at room temperature and brittle.
3. Malleability Can be beaten into sheets. Non-malleable.
4. Ductility Can be drawn into wires. Non-ductile.
5. Heat Conduction Present. Absent.
6. Conduction of electricity Possible. Not Possible.

Question 6.
Give reasons for the following :
(a) Aluminium foils are used to wrap food items.
(b) Immersion rods for heating liquids are made up of metallic substances.
(c) Copper cannot displace zinc from its salt solution.
(d) Sodium and potassium are stored in kerosene.
Answer:
(a) Aluminium foils are used to wrap food items because aluminium is malleable and less reactive to air and water.

(b) Immersion rods for heating liquids are made of metallic substances because metals are good conductors of heat and electricity.

(c) Copper is less reactive than zinc. As a result it cannot replace zinc from its salt solution.

(d) Sodium and potassium are very reactive metals. They react with air and water to form respective oxides and hydroxides. So, they are kept in kerosene.

Question 7.
Can you store lemon pickle in aluminium utensil ? Explain.
Answer:
No. Lemon pickle cannot be stored in aluminium utensils because acid present in lemon pickle reacts with aluminium to produce poisonous chemicals, which can cause food poisoning or other health hazards.

Question 8.
Match the substances given in Column A with their uses given in Column B.

Column A Column B
(i) Gold (a) Thermometers
(ii) Iron (b) Electric wire
(iii) Aluminium (c) Wrapping food
(iv) Carbon (d) Jewellery
(v) Copper (e) Machinery
(vi) Mercury (f) Fuel

Answer:

Column A Column B
(i) Gold (d) Jewellery
(ii) Iron (e) Machinery
(iii) Aluminium (c) Wrapping food
(iv) Carbon (f) Fuel
(v) Copper (b) Electric wire
(vi) Mercury (a) Thermometers.

PSEB 8th Class Science Solutions Chapter 4 Materials: Metals and Non-Metals

Question 9.
What happens when
(a) Sulphuric acid is poured on a copper plate ?
(b) Iron nails are placed in copper sulphate solution ?
Write word equations of the reactions involved. (From Board M.Q.P.)
Answer:
(a) When sulphuric acid is poured on copper plate, Hydrogen gas is given out.
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 1

(b) When iron nails are placed in copper sulphate solution, iron displaces copper from its salt to form iron sulphate
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 2

Question 10.
Saloni took a piece of burning charcoal and collected the gas evolved in a test tube.
(а) How will she find the nature of the gas ?
(b) Write down word equations of all the reactions taking place in this process.
Answer:
(a) To test the nature of the gas:
1. Take blue/red litmus solution turnwise into the jar of gas collected. It will turn blue litmus red while red litmus will remain unaffected. This shows that gas is acidic in nature.
2. Add some water to the jar. The liquid for turns blue litmus red showing acidic nature of the gas.

(b) When a charcoal is burnt, it reacts with oxygen to form an acidic oxide called
carbon dioxide.
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 3

The acidic oxide, carbondioxide, dissolves in water to form an acid called Carbonic acid
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 4

Question 11.
One day Reeta went to a jeweller’s shop with her mother. Her mother gave an old gold jewellery to the goldsmith to polish. Next day when they brought the jewellery back, they found that there was a slight loss in its weight. Can you suggest a reason for the loss in weight ?
Answer:
Jewellers usually use a chemical solution named aquaregia for cleansing the jewellery. This solution is capable of dissolving gold in it. So, loss in weight is found.

Multiple Choice Questions

Question 1.
In order to keep the flow of electricity continue in circuit, which of the following items should be used in place of iron nail in the given circuit. (From Board M.Q.P.)
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 5
(a) Graphite
(b) Plastic
(c) Wood
(d) Rubber.
Answer:
(a) Graphite.

Question 2.
Sodium metal is stored ………………….
(a) In water
(b) In kerosene oil
(c) In Air
(d) None of these.
Answer:
(b) In kerosene oil.

Question 3.
When strip of iron is placed in moist air then after some days a layer is deposited over it which has colour:
(a) Green
(b) Red
(c) Dirty
(d) None of these.
Answer:
(b) Red.

Question 4.
Which of the following statements is correct ?
(a) All metals are ductile
(b) All non-metals are ductile.
(c) Generally metals are ductile
(d) Some non-metals are ductile.
Answer:
(c) Generally metals are ductile.

PSEB 8th Class Science Solutions Chapter 4 Materials: Metals and Non-Metals

Question 5.
Which of the following is a non-metal ?
(a) Iron
(b) Carbon.
(c) Gold
(d) Calcium.
Answer:
(b) Carbon.

Question 6.
Phosphorus is stored in:
(a) Water
(b) Air
(c) Oil
(d) None of the above.
Answer:
(a) Water

Question 7.
The metal which is found in liquid form is:
(a) Copper
(b) Silver
(c) Mercury
(d) Sodium.
Answer:
(c) Mercury.

Question 8.
Which metal is a good conductor of electricity and heat ?
(a) Sodium
(b) Potassium
(c) Copper
(d) None of the above.
Answer:
(c) Copper.

Question 9.
The best conductor of electricity is:
(a) Copper
(b) Lead
(c) Aluminium
(d) Silver.
Answer:
(d) Silver

Question 10.
Red colour makes the solution of litmus blue because of:
(a) Metal oxide
(b) Sulphur dioxide
(c) Carbondioxide i
(d) None of the above.
Answer:
(a) Metal oxide.

Question 11.
Non-metal on the base of hardness is:
(a) Iron
(b) Aluminium
(c) Copper
(d) Coal.
Answer:
(d) Coal.

PSEB 8th Class Science Solutions Chapter 4 Materials: Metals and Non-Metals

Question 12.
Which of the following gas is released when a metal react with acids ?
(a) Oxygen
(b) Hydrogen
(c) Sulphur dioxide
(d) Nitrogen
Answer:
(b) Hydrogen.

Very Short Answer Type Questions

Question 1.
Name the property because of which metals can be beaten into thin layers or sheets.
Answer:
Malleability.

Question 2.
What is ductility ?
Answer:
Ductility. The property by which metals can be drawn into wires, is called ductility.

Question 3.
Name the most ductile metal.
Answer:
Silver.

Question 4.
Name the metal which exists in the liquid state.
Answer:
Mercury.

Question 5.
Name one metal which is poor conductor of electricity.
Answer:
Lead.

Question 6.
Which metal is used in thermometer ?
Answer:
Mercury.

PSEB 8th Class Science Solutions Chapter 4 Materials: Metals and Non-Metals

Question 7.
Which metal and non-metal is liquid at ordinary temperature ?
Answer:
Metal – Mercury
Non-Metal – Bromine.

Question 8.
Write two properties of metals.
Answer:
Malleability and Ductility.

Question 9.
Name two metals which are good conductors of both heat and electricity.
Answer:
Copper and Aluminium are good conductors of both heat and electricity.

Question 10.
Name three metals which occur in the native state.
Answer:

  1. Silver
  2. Gold
  3. Platinum occur in the native state.

Question 11.
List two metals which are easy to cut.
Answer:

  1. Sodium
  2. Potassium.

Question 12.
What is that property, which allows metals to be drawn into wires, called ?
Answer:
Ductility.

Question 13.
Which metals are used to make electric wires ?
Answer:
Copper and Aluminium.

PSEB 8th Class Science Solutions Chapter 4 Materials: Metals and Non-Metals

Question 14.
Which metal is constituent of haemoglobin ?
Answer:
Iron.

Question 15.
Write a chemical reaction of Iron with Oxygen.
Answer:
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 6

Question 16.
Write the chemical equation for the reaction of Zn with Oxygen.
Answer:
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 7

Question 17.
The set of metals in order of their increasing chemical reactivity is given below:
Silver, copper, lead, iron, zinc, magnesium and sodium.
(a) Which of the above metals is stored in kerosene ?
(b) Which metals will react with cold water ?
(c) Which gas will be liberated when metals react with cold water ?
(d) Which of the metals will react with oxygen when heated ?
(e) Which of the metals becomes black in the presence of hydrogen sulphide, H2S ?
(f) Which of the metals burns with white bright flame in oxygen ?
Answer:
(a) Sodium
(b) Sodium and Magnesium
(c) Hydrogen
(d) Magnesium
(e) Silver
(f) Magnesium.

Question 18.
Name five metals which are used in daily life.
Answer:
Metals used in daily life.

  1. Aluminium
  2. Iron
  3. Copper
  4. Zinc
  5. Tin.

Question 19.
Name five metals which are used in our industrial processes.
Answer:
Metals used in Industrial Processes.

  1. Aluminium
  2. Iron
  3. Copper
  4. Nickel
  5. Zinc.

Question 20.
Why do Sodium, Zinc, Magnesium and Aluminium not occur in their pure state ?
Answer:
Because these react with air, water and acids.

PSEB 8th Class Science Solutions Chapter 4 Materials: Metals and Non-Metals

Question 21.
Name atleast two metals which do not react with air, water and acids.
Answer:

  1. Gold
  2. Platinum.

Question 22.
Of what property, are metals used in jewellery ?
Answer:
Metallic lustre.

Question 23.
What is the colour of copper metal ?
Answer:
Eeddish-brown colour.

Question 24.
Of Iron, Copper and Magnesium, which metal can be cut easily ?
Answer:
Magnesium.

Short Answer Type Questions

Question 1.
What is the difference between a metal and a non-metal ? What is the total number of naturally occurring elements ?
Answer:
Metals have metallic lustre, are malleable, ductile, good conductors of heat and electricity, hard and combine with oxygen to form basic oxides.

Non-metals have dull lustre, not malleable and non-ductile, bad conductors of heat and electricity, brittle and combine with oxygen to form acidic oxides. The total number of naturally occurring elements is 92.

Question 2.
Why is Potassium metal not stored in water ?
Answer:
Potassium is a reactive metal. It reacts with air even at room temperature. Also it reacts with water at room temperature and catches fire. Hence, it is not stored in water but kept under kerosene oil.
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 8

Question 3.
State two physical properties on the basis of which metals may be distinguished from non-metals.
Answer:

  1. Metals are good conductors of heat and electricity. Non-metals are bad conductors of heat and electricity.
  2. Metals have a shiny appearance, that is, they show a metallic lustre. Nonmetals have a dull lusture. They generally do not reflect light well.

PSEB 8th Class Science Solutions Chapter 4 Materials: Metals and Non-Metals

Question 4.
State one chemical property which may be used to distinguish a metal from a non-metal.
Answer:
Metals when burn, combine with oxygen to form metallic oxides which are basic in nature, whereas non-metals combine with oxygen to form acidic oxides. This property can be used to distinguish a metal from a non-metal.

Question 5.
Why is sodium stored in kerosene oil ?
Answer:
Sodium is highly reactive metal. It readily combines with oxygen when exposed to air and sometimes it even catches fire. It also reacts with water forming its hydroxide. To prevent its oxidation, sodium is stored under kerosene oil.

Question 6.
Explain the following:
(а) Acidic oxides
(b) Basic oxides.
Answer:
(a) Acidic Oxides. These are the oxides of non-metals and give acids when dissolved in water.
Examples : CO2, SO2 etc.

(b) Basic Oxides. These are the oxides of metals and give alkaline or basic solutions in water.
Examples : Sodium oxide, Calcium oxide etc.

Question 7.
Explain the occurrence of metals in nature.
Answer:
Occurrence of Metals in Nature. Metals occur in the nature in free as well as in combined state.
1. Free or Native State. The metals which are not attacked by air and moisture generally occur in the free or native state e.g. metals like gold, platinum etc.

2. Combined State. Metals generally occur in nature in the form of compounds
such as oxides, sulphides etc. These metals are said to occur in the combined state, e.g. Aluminium oxide.

Question 8.
What do you understand by ductility and malleability of a metal ? Give examples of two metals which are both ductile and malleable.
Answer:
Ductility.
It is the property of metals by virtue of which metals can be drawn into thin unbroken wires. Metals exhibiting this property are called ductile.
Examples : Copper, Aluminium, Silver, Gold.

Malleability. It is the property of metals by virtue of which Metals which can be beaten into thin sheets and twisted or bent without breaking. Metals showing this property are called malleable.
Examples : Gold, Silver, Aluminium.
Examples of two metals which are both malleable and ductile :
Aluminium and Gold.

Question 9.
Silver does not combine easily with oxygen but silver jewellery tarnishes after some time. How ?
Answer:
Silver does not combine easily with oxygen of the air. But it readily combines with sulphur compounds such as hydrogen sulphide present in the air to form a black coating of silver sulphide. Therefore, silver jewellery tarnishes after some time.

Question 10.
Why do gold ornaments look new even after several years of use ?
Answer:
Gold does not tarnish. That is, it never corrodes as it is non-reactive. It is unaffected by air, water and acids. This is why gold ornaments look new even after several years of use.

PSEB 8th Class Science Solutions Chapter 4 Materials: Metals and Non-Metals

Question 11.
Magnesium and copper metals are heated directly over a flame. Which of these will burn in air ? Which is more reactive ?
Answer:
When magnesium and copper are heated directly over a flame, magnesium will burn in air. Magnesium is more reactive.

Question 12.
CuSO4 + Fe → FeSO4 + Cu
FeSO4 + Zn → ZnSO4 + Fe
On the basis of the above reactions, indicate which is the most reactive and which is the least reactive metal out of zinc, copper and iron ?
Answer:
In the first reaction, iron displaces copper from copper sulphate solution, therefore, iron is more reactive than copper. In the second reaction zinc displaces iron from iron sulphate, therefore, zinc is more reactive than iron. Therefore, zinc is the most reactive metal while copper is the least reactive.

Question 13.
Why are pickles, chutney and citrus fruits not stored in iron and aluminium utensils ?
Answer:
Certain foodstuffs, particularly citrus fruits, chutney, pickles and curd, which contain acids tend to attack kitchen utensils made of aluminium and iron forming poisonous salts. Iron and aluminium utensils are, therefore, not used to store pickles, chutney and citrus fruits.

Question 14.
What would you observe when a strip of zinc is dipped in the solution of copper sulphate ?
Answer:
Zinc being more reactive would replace copper from its salt solution i.e. copper sulphate.
Zn + CuSO4 → ZnSO4 + Cu

Question 15.
Can copper displace iron from iron sulphate solution ? Give reasons.
Answer:
No, because copper is less reactive than iron. As a result, it can’t replace iron from its salt solution i.e. iron sulphate. Only more reactive metals can replace less reactive metals from their salt solutions. Vice-versa is not possible i.e., less reactive metals cannot replace more reactive metals from their salt solutions.

Question 16.
Why does aluminium vassel lose its lusture after sometime ?
Answer:
Aluminium is a reactive metal. During its use, it comes in contact with air and water when it forms dull coating of aluminium oxide on its surface. Hence the vessel loses its shine.

PSEB 8th Class Science Solutions Chapter 4 Materials: Metals and Non-Metals

Question 17.
Why aluminium metal is preferred to copper for making cooking utensils ? Give two reasons.
Answer:
Because of the following two reasons, aluminium is preferred to copper for making cooking utensils.

  1. It is very light and is a good conductor of heat.
  2. It is not readily attacked by acids present in the food materials to be cooked.

Question 18.
What is corrosion ? What are the different ways to reduce corrosion ?
Answer:
Corrosion. Metals when exposed to moist air get covered with dull layer.
This layer can be easily removed giving place to the next such layer to be formed. In this way, metal is eaten up or corroded and the process is called corrosion.
Ways to reduce corrosion:

  1. By covering the metal with paint
  2. By applying oil or grease on the surface of metal.
  3. By coating the metal with some other metal which is not easily corroded by passing electricity.
  4. By making an alloy.

Question 19.
Sodium occurs in the combined state where as Gold in its native state, why ?
Answer:
Sodium is the most reactive metal. It readily combines with air and water to form its compounds. So it occurs as compound. On the other hand Gold is the noble metal and is not attacked by air, water or acids so it exists in its native form.

Question 20.
Does copper rust ? What will happen if copper is exposed to moist air ?
Answer:
Copper does not rust. When copper is exposed to moist air for long, it acquires a dull green coating. The green material so formed is a mixture of Copper hydroxide [CU(OH)2] and Copper carbonate [CuCO3], The following reaction takes place:
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 9

Question 21.
Give reasons for the following:
(i) Aluminium is used in making parts of aeroplane.
(ii) Copper is used in making electric wires.
(iii) Silver is used in making mirrors.
(iv) Graphite is used as an electrode in the Dry cell.
(v) Iron is used in constructing bridges and dams.
Answer:
(i) Aluminium being light and strong metal is used in making parts of aeroplanes.
(ii) Copper is a good conductor of electricity. So, it is used for making electric wires.
(iii) Silver is very shining white metal and has, therefore, high reflecting power.
(iv) Graphite is a good conductor, so it used for making electrode in dry cells.
(v) Iron being strong and rigid metal is used in the construction of bridges and dams.

PSEB 8th Class Science Solutions Chapter 4 Materials: Metals and Non-Metals

Long Answer Type Questions

Question 1.
Give general physical properties of metals.
Answer:
General physical properties of metals:

  1. Metals have a shiny appearance, i.e. they show metallic lustre.
  2. Metals are generally hard and their hardness varies from metal to metal.
  3. Most metals are malleable, i.e. they can be hammered into thin sheets.
  4. Metals are ductile and, therefore, can be drawn into wires.
  5. Metals are good conductors of heat and electricity. Electricity flows most readily through gold, silver, copper and aluminium.
  6. Metals are generally sonorous i.e. metals make sound when hit with an object.
  7. All metals except mercury exist in solid form at room temperature.
  8. Metals have high melting points.

Question 2.
Give general physical properties of non-metals.
Answer:
General physical properties of non-metals:

  1. Lustre. Non-metals possess dull lustre, i.e., they do not reflect light well. Exceptions are graphite and diamond.
  2. Conductivity. Non-metals are poor conductors of heat and electricity. Exception is graphite.
  3. State. Non-metals may occur as solids or liquids or gases at room temperature. For example Sulphur, Carbon and Iodine are solids. Bromine is a liquid. Chlorine and nitrogen are gases.
  4. Malleability. Non-metals are not malleable but they are brittle. Non-metals break into small pieces when hammered.
  5. Hardness. Non-metals are generally not hard but diamond is exception. Diamond is the hardest known substance.
  6. Ductility. Non-metals cannot be drawn into wires and are, therefore, not ductile
  7. Melting and Boiling Point. Non-metals have low melting and boiling points. A majority of non-metals are gases. Exception is graphite which has a high melting point.

Question 3.
How do metals react with acids ?
Answer:
Reaction of metals with acids :
1. Active metals like zinc, magnesium, iron etc. which lie above hydrogen in the electrochemical series or activity series can displace hydrogen from dilute mineral acids such as hydrochloric acid and sulphuric acid.
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 10

2. The metals which lie below hydrogen don’t displace hydrogen from dilute mineral acids such as hydrochloric acid, sulphuric acid etc.
For example, copper does not react with dil. HCl.

Question 4.
How do metals react with water ?
Answer:
Reaction of metals with water. Different metals have different reactivities with water. All metals react with water under different conditions to produce hydrogen gas.
1. Active metals like Na, K react with water at room temperature.
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 11
The reaction is so violent and exothermic that the evolved hydrogen catches fire.

2. Less active metals like Mg, Zn, Al, react with boiling water.
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 12
3. Metals like Fe, Ni react very mildly with steam
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 13

PSEB 8th Class Science Solutions Chapter 4 Materials: Metals and Non-Metals

Question 5.
Which of the following displacement reaction cannot occur ?
(a) CUSO4(aq) + Fe → FeSO4(aq) + Cu
(b) FeSO4(aq) + Zn → ZnSO4(aq) + Fe
(c) ZnSO4(aq) + Pb → PbSO4(aq) + Zn
(d) 2AgNO3(aq) + Cu → Cu(NO3)2 + 2Ag
(e) MgSO4(aq) + Cu → CuSO4 + Mg
Answer:
A more reactive metal (placed higher in the activity series) can displace the less reactive metal from its solution. Out of the above five reactions.
(c) cannot occur because zinc is more reactive than lead.
(e) cannot occur because magnesuim is more reactive than copper.

Question 6.
Name three metals that you come across in your daily life and also give their uses.
Answer:
We come across directly or indirectly the following metals in our daily life:

  1. Iron
  2. Copper
  3. Aluminium

1. Uses of Iron :

  • Iron mixed with other metals is largely used in making trains, automobiles and other machine parts.
  • Iron mixed with cement is used in constructing big buildings and dams.
  • Iron is used in making bridges and boilers for industry.

2. Uses of Copper:

  • It is used for making cooking utensils,
  • It is used in making photoframes, coins and statues.
  • It is used for making electrical wires.

3. Uses of Aluminium:

  • It is used for making aeroplanes
  • It is used for making electric wires and parts of electric gadgets.
  • Aluminium foils are used as packing material.

Question 7.
Distinguish between metals and non-metals on the basis of their chemical properties.
Answer:
Distinction between Metals and Non-metals

Property Metals Non-Metals
Chemical Properties-

1. Nature of Ions

 Metals are electr-opositive elements and lose electrons to become electro-positive ions. Non-metals are electro-negative elements and gain electrons to form negative ions.
2. Nature of Oxides Form basic oxides Form acidic oxides.
3. Reaction with Water Mostly displace hydrogen. Do not react with water.
4. Reaction with Acids Metals above hydrogen in the activity series displace hydrogen from Non-metals do not react with dilute acids.
5. Nature of Hydrides Metals react with hydrogen to form ionic hydrides. Form covalent hydrides.
6. Nature of Chlorides Metals combine with chlorine to form solid ionic chlorides which conduct electricity. Non-metals combine with chlorine to form covalent chlorides which do not conduct electricity.

Question 8.
Give general chemical properties of non-metals.
Answer:
1. Reaction with Air or Oxygen. Non-metals react with air or oxygen to form their corresponding oxides which are acidic in nature. These oxides turn blue litmus red.
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 14

2. Reaction with Hydrogen. Non-metals like carbon, Nitrogen, and Phosphorous react with Hydrogen to form different compounds.
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 15

3. Reaction with other non-metals. Non-metals react with other non-metals to form compounds
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 16

4. Reaction with Acids. Non-metals react with acids to form corresponding oxyacids.
PSEB 8th Class Science Solutions Chapter 4 Materials Metals and Non-Metals 17

PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management

by

Punjab State Board PSEB 8th Class Science Book Solutions Chapter 1 Crop Production and Management Textbook Exercise Questions and Answers.

PSEB Solutions for Class 8 Science Chapter 1 Crop Production and Management

PSEB 8th Class Science Guide Crop Production and Management Textbook Questions and Answers

Exercises

Question 1.
Select the correct word from the following list and fill in the blanks:
float, water, crop, nutrients, preparation
(a) The same kind of plants grown and cultivated on a large scale at a place is called ……………..
Answer:
crop

(b) The first step before growing crops is …………………. of the soil.
Answer:
preparation

(c) Damaged seeds would ………………… on top of water.
Answer:
float

(d) For growing of crop, sufficient sunlight, ……………… and ……………… from the soil are essential.
Answer:
water, nutrients

Question 2.
Match items in colun,.n ‘A’ with those in column ‘B’:

(A) (B)
(i) Kharif crops (a) Food for cattle
(ii) Rabi crops (b) Urea and super phosphate
(iii) Chemical fertilizers (c) Animal excreta, cow dung, urine and plant waste
(iv) Organic manure (d) Wheat, gram and pea
(e) Paddy and maize

Answer:

(A) (B)
(i) Kharif crops (e) Paddy and maize
(ii) Rabi crops (d) Wheat, gram and pea
(iii) Chemical fertilizers (b) Urea and super phosphate
(iv) Organic manure (c) Animal excreta, cow dung, urine and plant waste

PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management

Question 3.
Give two examples of each.
(a) Kharif Crop
(b) Rabi Crop
Answer:
(a) Kharif Crop – (i) Paddy (ii) Maize.
(6) Rabi Crop – (i) Wheat (ii) Gram.

Question 4.
Write a paragraph in your own words on each of the following:
(a) Preparation of soil
(b) Sowing
(c) Weeding
(d) Threshing.
Answer:
(a) Preparation of Soil.
Soil is loosened and overturned to make it better ventilated and suitable for the growth of tiny organisms living in it. The entire process is called tillage and ploughing.

Soil if ploughed in dry season gets into big mud pieces or crumbs. These are broken down by plying a soil plank.
The ploughed soil is liable to be removed by wind and water. Wooden leveller is used to press the soil.

(b) Sowing.
The process of putting seeds in the soil is called sowing. It is the most important part of crop production. Before sowing, good quality of seeds are selected. The seeds are sown in the fields by hand (broadcasting) and by seed drill.

(c) Weeding.
It is a process of removal of unwanted plants i.e. weeds from the fields. It is necessary to remove the weeds since they compete with the main crop for water, nutrients, sunlight etc. The weeds may be removed manually by uprooting or cutting. The best time to remove them is before they produce flowers and seeds. It is done with a khurpi and a tractor driven harrow. Some chemicals called weedicides are used to control the weeds. They are sprayed in the fields for killing the weeds e.g. linazine, dalapon, etc.

(d) Threshing.
The separation of grains from the chaff in the harvested plants is called threshing. Animals are used on a large scale for threshing. In large farms, a machine called ‘thresher’ or a motorized machine called ‘combine’ are used for both harvesting and threshing.

Question 5.
Explain how fertilizers are different from manure.
Answer:
Differences between Manure and Fertilizers

Fertilizers Manure
1. These are mixtures of chemical compounds rich in nitrogen, phosphorus, potassium and manufactured in factories. 1. These are organic substances prepared from the decomposition of plant and animal wastes.
2. Chemical fertilizers are nutrients specific i.e. nitrogenous, phosphatic, etc. 2. They contain a mixture of various nutrients recycled from biomass wastes.
3. They are in a concentrated form. 3. They are not in a concentrated form.
4. They are easy to store or transport. 4. They are not easy to store or transport.
5. They are harmful if used in excess. 5. They are never harmful to the soil.

Question 6.
What is irrigation ? Describe two methods of irrigation which conserve water.
Answer:
Irrigation. Giving water to the fields at different intervals is called irrigation. The time and frequency of irrigation varies from crop to crop, soil to soil and season to season.

The latest irrigation methods help us to use water economically. The main methods used which conserve water are as follows:

1. Sprinkler System.
This system is more useful on the uneven lands where water is available in smaller quantity. The perpendicular pipes, having rotating nozzles on the top, are joined to the main pipe line at regular intervals. The water is allowed to flow through it with the help of a pump. The water escapes from the rotating nozzles. It is sprinkled on the crop as if it is raining. Sprinkler method is very useful for the sandy soil.

2. Drip System.
In this system, the water falls drop by drop just at the position of the roots. So it is called drip system.
Fig. Sprinkler System.
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 1
It is the best technique of watering fruit plants, gardens and trees. Drip system consists of a main pipe to which lateral pipes are joined. The specially prepared nozzles are attached to these lateral pipes. It provides water to plants drop by drop. In this way, water is not wasted. So, it is a boon in regions where availability of water is poor.
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 2

Question 7.
If wheat is sown in the Kharif season, what would happen ? Discuss.
Answer:
Wheat is a Rabi crop i.e. it is grown in winter season where there is low temperature and needs less water. So, if wheat is sown in Kharif season during rainy season, it gets more water which is harmful to the crop. The wheat crop droops down. It would not grow healthy.

PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management

Question 8.
Explain how soil gets affected by the continuous plantation of crops in a field.
Answer:
For the continuous plantation and better growth of crops, manure and fertilizers are added regularly in the field. Manure and fertilizers are the nutrients like nitrogen, phosphorus, potassium etc. They can change the nature of the soil. The soil may become more alkaline or acidic with addition of the nutrients.

Question 9.
What are weeds ? How can we control them ?
Answer:
Weeds. Weeds are undesirable plants that may grow naturally along with the crop. The removal of weeds is called weeding.

Methods to Control Weeds. Following methods are used to control the weeds:

  • Tilling. The process of loosening and turning of the soil is called tilling or ploughing. This is done by using plough. Tilling helps in uprooting and killing of weeds.
  • Manual Removal. This method includes the physical removal of weeds by uprooting or cutting them close to the ground. This is done with the help of Khurpa or Harrow.
  • Chemical Method. In this method weeds are controlled by using some chemicals, called weedicides like 2, 4-D. The weedicides are sprayed in the fields with a sprayer.

PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 3

Question 10.
Arrange the following boxes in proper order to make a flow chart of sugarcane crop production.
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 4
Answer:
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 5

Question 11.
Complete the following word puzzle with the help of clues given below.
Down
1. Providing water to the crops.
2. Keeping crop grains for a long time under proper conditions.
5. Certain plants of the same kind grown on a large scale.

Across
3. A machine used for cutting the matured crop.
4. A rabi crop that is also one of the pulses.
6. A process of separating the grain from chaff.
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 6
Answer:
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 7

PSEB Solutions for Class 8 Science Crop Production and Management Important Questions and Answers

Multiple Choice Questions

Question 1.
The following implement is related to which agriculture practice.
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 8
(a) Irrigation
(b) Sowing
(c) Weeding
(d) Harvesting.
Answer:
(d) Harvesting.

Question 2.
The figure given below represents which conventional method of irrigation ?
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 9
(a) Pulley
(b) Chain Pump
(c) Dhekli
(d) Rahat.
Answer:
(c) Dhekli.

Question 3.
Mohan is sprinkling chemical solution to destroy weed plants growing along with main crops in his field. What is this chemical solution called ?
(a) Fertilizer
(b) Weedicides
(c) Yeast
(d) None of the above.
Answer:
(b) Weedicides.

PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management

Question 4.
The mother of Naresh collects the waste material of living beings in an open space. According to her, after a few days, micro-organisms break the waste material of living beings and turn it into fertilizers. What is this fertilizer called ?
(a) Fertilizer
(b) Chemical fertilizer
(c) Manure
(d) None of the above.
Answer:
(c) Manure.

Question 5.
Jasbeer saw some weeds (unwanted plants) growing in his field along with main crops. What is this process called in which these weeds are removed from the field ?
(a) Sowing
(b) Irrigating
(c) Weeding
(d) Cutting.
Answer:
(c) Weeding.

Question 6.
In which season Kharif crops are grown ?
(a) Rainy season
(b) Autumn season
(c) Winter season
(d) None of the above.
Answer:
(a) Rainy season.

Question 7.
The process of loosening and overturning the soil is called:
(a) Ploughing
(b) Sowing
(c) Irrigation
(d) Weeding.
Answer:
(a) Ploughing.

Question 8.
The roots of bean plants have nodules and the microorganism which lives inside them is called:
(a) Virus
(b) fungi
(c) Rhizobium bacterium
(d) Algae
Answer:
(c) Rhizobium bacterium.

Question 9.
Which weedicides are used to remove weeds from the crops ?
(a) 2.4 D
(b) B.H.C.
(c) DDT
(d) All of the above.
Answer:
(a) 2.4 D.

Question 10.
What percentage of water is in plants ?
(a) 70%
(b) 80%
(c) 60%
(d) 90%
Answer:
(d) 90%.

Question 11.
Weeds are:
(a) Unwanted plants growing along with main crops
(b) Crop plants
(c) Bean plants
(d) Useful plants
Answer:
(a) Unwanted plants growing along with main plants.

PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management

Question 12.
Which of the following is not the source of irrigation ?
(a) Well
(b) Sea
(c) River
(d) All of the above.
Answer:
(b) Sea.

Question 13.
The modern method of irrigation is
(a) Dhekli
(b) Chain pump
(c) Rahat
(d) Sprinkle system.
Answer:
(d) Sprinkle system.

Very Short Answer Type Questions

Question 1.
Define agriculture.
Answer:
Agriculture. The word agriculture consists of two Latin words – ager means field and culture means cultivate. So, agriculture is defined as to cultivate the fields.

Question 2.
What is staple Food ?
Answer:
Staple food. The food which forms the main part of our diet is called staple food e.g. rice and wheat. These are grown on a large scale in vast fields as they are consumed in large amounts.

Question 3.
What time does a crop take to mature ?
Answer:
It normally takes about 3-4 months for a good crop to mature.

Question 4.
What are weedicides ?
Answer:
Weedicides. Those chemicals which are sprayed over the field to check the growth of the weeds are known as weedicides.

Question 5.
What is animal husbandry ?
Answer:
Animal Husbandry. The study of all aspects such as food, shelter, health care of domesticated animals is called animal husbandry.

Question 6.
What is crop ?
Answer:
Crop. The plants of the same kind grown at a place is referred to as crop.

PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management

Question 7.
Name two main crops of our country.
Answer:
Main crops of country. Wheat and Paddy are two main crops of India.

Question 8.
Define Produce.
Answer:
Produce. The crops are grown on ground or in water and what we obtain from the crop is called produce.

Question 9.
What are Kharif crops ?
Answer:
Kharif Crops. The crops grown during June-October are called Kharif crops, for example, paddy, maize.

Question 10.
What are Rabi crops ?
Answer:
Rabi Crops. The crops grown during November-April are called Rabi crops. These are not based on monsoon.
Example. Wheat, legumes like clover.

Question 11.
Name three crops sown by sowing seeds.
Answer:
Wheat, maize and millet.

Question 12.
Define irrigation.
Answer:
Irrigation. The supply of water at different levels is called irrigation.

Question 13.
Name two legume crops.
Answer:
Clover (barseem) and Gram.

PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management

Question 14.
What is weeding ?
Answer:
Weeding. The removal of weeds is called weeding.

Question 15.
What is crop rotation ?
Answer:
Crop rotation. Sowing of different crops alternately in the field is called crop rotation.

Short Answer Type Questions

Question 1.
Why is soil turned and loosened before seeds are sown ?
Answer:
Soil is turned and loosened before seeds are sown because of following reasons:

  1. It allows the roots to penetrate freely and deeper.
  2. It allows the roots to breathe easily.
  3. The plant is secured more firmly.
  4. It aids the growth of worms and microbes present in the soil.

Question 2.
What are broadcasting and transplanting ?
Answer:
Broadcasting.
After the soil has been prepared, seeds of crop plants are sown in it. There are two methods of sowing them. Sowing by land or by using seed drill is called broadcasting.

Transplanting.
It is a process of taking out young plants or seedlings from nursery beds and transfer them to fields with required spacing, water and minerals for adequate growth.
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 10

Question 3.
What are insecticides ?
Answer:
Insecticides.
The special chemicals which selectively kill the pests or harmful insects as well as their eggs and larvae, but do not affect the plants are called insecticides or pesticides.

Question 4.
Why should the harvested grains be protected from moisture ?
Answer:
Moisture and humidity promotes the growth of fungi or moulds on grains. Some of these microorganisms are poisonous also. So, it is very important to store harvested grains dry.

Question 5.
How does a farmer rotate crops in the fields ?
Answer:
Crop rotation involves the change of crop every year as alternate sowing of crops so that pathogen is killed in absence of suitable host.

Repeated growing of the same plant however may deplete the soil severely of specific nutrients. To prevent this it is advisable to cultivate two different types of plants alternately. For example, maize and wheat are grown alternately with groundnut. The groundnut plant, with its nitrogen fixing, bacteria enriches the soil with some nutrients, which are beneficial for wheat. Rotating different crops in this manner thus replenishes the soil naturally.

PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management

Question 6.
How are pests controlled in a crop field ?
Answer:
Pests are living organisms which cause diseases or kill or destroy the crop plants. In order to control the pests, pesticides such as Malathion, Disyston, B.H.C. etc. are used. They are sprayed on the crops. They kill the microbes without causing harm to plants and human beings who consume them.
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 11

Question 7.
What are the harms of excess of water in the fields ?
Answer:
Harms of excess of water

  1. It can destroy crops.
  2. Continued water logging increases the amount of salt in the soil and can damage it permanently.
    Excess water can be drained off by providing a suitable outlet.

Question 8.
Why is it important to wash off fruits, grains or vegetables before being consumed ?
Answer:
It is important to wash off fruits, grains or vegetables because these when brought from fields to the market often have a coating of pesticides. Otherwise they prove to be harmful.

Question 9.
What is field fallow ? Why is it important ?
Answer:
Field Fallow.
Some fields are allowed to rest and regenerate for at least a season to support a crop. This is called field fallow.

Importance.
The growth of humus picks up which in turn promotes the growth of soil micro-organisms during such undisturbed periods. It leads to a rich replenishment of nutrients.

Question 10.
How are the stored grains damaged ?
Answer:
Rats and other rodents damage the stored grains. The amount of grain eaten by rats and rodents is estimated to be over 25% of the total produce.
Stored grains are also damaged by insects and worms. Such infested grains if consumed by people, cause many diseases.

Question 11.
What are weeds ? How are they removed ?
Answer:
Weeds. Weeds are undesirable plants that may grow naturally along with the crop. The removal of weeds is called weeding.

Methods to Control Weeds. Following methods are used to control the weeds:
1. Tilling. The process of loosening and turning of the soil is called tilling or ploughing. This is done by using plough. Tilling helps in uprooting and killing of weeds.
2. Manual Removal. This method includes the physical removal of weeds by uprooting or cutting them close to the ground. This is done with the help of Khurpa or Harrow.
3. Chemical Method. In this method weeds are controlled by using some chemicals, called weedicides like 2, 4-D. The weedicides are sprayed in the fields with a sprayer.
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 3

Question 12.
Give the structure of harrow. What is its main use ?
Answer:
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 12
Structure of Harrow. It has small pointed iron rods or wooden rods. A strong, broad plate of iron is fixed to one of its ends and works like a blade. It uproots the weeds when moved in a crop field just like a plough.

Uses. It is used to remove the weeds of the field.
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 13

PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management

Question 13.
Why is ploughing of soil necessary before sowing seeds or crop plants ?
Answer:

  1. Ploughing tills the soil deeply. It may involve partial or complete turning over of soil.
  2. Ploughing clears land of the preceding crop and leaves the soil loosened.
  3. Repeated ploughing eliminates all weeds.
  4. Harmful insects are destroyed by ploughing.
  5. Ploughing makes the soil porous.
  6. Ploughing makes the soil soft, clean and suitable for sowing.

Question 14.
Why are fields manured ?
Answer:
Manuring of Fields.
Plants get their nutrients from the soil. If crops are grown continuously, they use all the nutrients present in the soil. To make up this deficiency of soil, manures are added to the soil.

Question 15.
What do you mean by harvesting and threshing ?
Answer:
Harvesting.
The cutting of the crop when it matures is called harvesting. Most of the crops are harvested with help of a sickle or huge combines.
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 14

Threshing.
The separation of grains from the chaff is called threshing. Animals are used on a large scale for threshing.

Question 16.
What are the types of crops on the basis of seasons ? Give examples of each type.
Answer:
Crops are of two kinds on the basis of season:

  1. Kharif Crops. The crops which are grown during the monsoon season are called Kharif Crops.
    Examples. Maize, Bajra and Cotton etc.
  2. Rabi Crops. Those crops which are grown during the winter season are called Rabi Crops.
    Examples. Wheat, Gram and Mustard etc.
  3. Summer Crops. Those crops which are grown during summer seasons are called Summer Crops.
    Examples. Moong, Water melon, Cucumber, gourd etc.

Question 17.
What is mixed cropping ? Give an example.
Answer:
Mixed Cropping.
The practice of cultivating two crops simultaneously is done to economise the time and energy. This is called mixed cropping.
Example. The crop of groundnut is grown in the fields along with cotton.

Question 18.
Why is it necessary to sow seeds at an appropriate depth ?
Answer:
It is necessary to sow seeds at an appropriate depth because if the seeds are sown too deep, they will not be able to germinate. On the other hand, if they are sown at a shallow depth, then they will be eaten away by birds or animals.

Question 19.
How is the crop produce stored ?
Answer:
The crop produce is stored in godowns by agencies like Food Corporation of India and State Warehousing Corporations. Grains are sun dried before storing to reduce moisture contents of grains. This prevents the attack of pests. Large scale storing of grains is done in granaries and silos to protect grains from pests like rats and insects.

PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management

Question 20.
Define Fertilizer.
Answer:
Fertilizers.
These are the chemical substances that are man-made and are rich in nitrogen, phosphorus and potassium, i.e. they are rich in organic macronutrients which are needed by plants.

Question 21.
Why should we use organic manures ?
Answer:
We should use organic manure because it helps in replenishing the soil nutrients without causing any harm to the soil. This manure is considered much better than the fertilizers. Crops like vegetables and fruits grown by organic manure are considered safe as compared to the crops grown by using chemical fertilizers. Therefore, we should use organic manure in growing vegetables and fruits.

Question 22.
Some seeds are given to you to grow. What factors will you keep in mind ?
Answer:
We will keep the following factors in mind. These are:

  1. We would sow them at the correct depth.
  2. We would water them regularly and check the amount of water that we are putting.
  3. We would use manure at the proper time.
  4. We would ensure that no weeds grow with the plant.
  5. We would also spray pesticides.
  6. We would also ensure that the plant gets adequate sunlight.

Question 23.
Why should we discourage the use of chemical fertilizers ?
Answer:
Chemical fertilizers are harmful in the following ways thus the use of such fertilizers be discouraged:

  1. They damage the soil by reducing its natural recomposting ability.
  2. They change the chemical nature of soil.
  3. These chemicals are leached in the soil and are again absorbed by crop plants and enter food chain and damage the plants and animals.

Question 24.
How do we store grains ? What is cold storage ?
Answer:
Storage of Grains.

  1. Farmers make small boxes of metal or mud to store dried grains. These are called granaries.
  2. Dried grains are transferred to properly ventilated cemented halls. These cemented halls are called godowns.
  3. The storage of some fruits and vegetables at a low temperature is called cold storage.

Question 25.
What are the basic requirements for growing a crop in an area ?
Answer:
The basic requirements for growing a crop in an area are as follows:

  1. Proper type of soil
  2. Use of manures
  3. Irrigation
  4. Better varieties of seeds
  5. Agricultural tools
  6. Chemicals to prevent diseases of the plant crop.

Question 26.
Why all the crops do not grow in the same season ?
Answer:
All crops do not grow in the same season because every crop has its own specific requirements of soil and climatic conditions like light, temperature and air at the various stages of its growth and development.

Question 27.
Do all the crops have identical requirements of manures and fertilizers ?
Answer:
No, every crop has specific requirements of manures and fertilizers for growth and development of the plants. Farmyard manure is useful for paddy crops. The groundnut plants have nodulated roots. These nodulated roots contain nitrogen-fixing bacteria which convert the atmospheric nitrogen into the compounds of nitrites and nitrates. For the crop of wheat, farmyard manure and green manure of sunhemp plants are mixed in the soil.

PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management

Question 28.
Write any two points of difference between Insecticides and Weedicides.
Answer:
Differences between insecticides and weedicides

Insecticides Weedicides
1. These are the chemicals used to kill the plant pests i.e. organisms attacking plants. 1. These are the chemicals used to kill the weeds i.e. unwanted plants.
2. These affect human life. 2. These enter food chain.
3. Examples : DDT, BHC etc. 3. Examples : Bulachlor 2-4D. Linazine, Dalapon etc.

Question 29.
What is transplanting ?
Answer:
Transplanting.
It is a process of taking out young plants or seedlings from nursery beds and transfer them to fields with required spacing, water and minerals for adequate growth.

Question 30.
Discuss the various tranditional ways of irrigation diagramatically.
Answer:
The various traditional ways are :
(a) Moat (Pulley system) (b) Chain pump (c) “Dhekli” (Lever system) (d) “Rahat” [Fig. (a) to (d)]. ‘
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 15
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 16
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 17
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 18
For lifting water, pumps are commonly used. Diesel, biogas, electricity and solar energy are used to run the pumps. The pumps of various power are available. They are selected according to the requirement of the particular field.

Long Answer Type Questions

Question 1.
Explain the main agricultural practices.
Answer:
Main agricultural practices. The main agricultural practices are as follows:

1. Ploughing.
The process of loosening and turning the soil is called ploughing. This is done by using a plough. Ploughs are made of wood or iron. The ploughed land is then levelled so that the soil is not blown off by wind or drained off by water.

2. Sowing.
After the preparation of the soil, the seeds are sown in the fields by hand (broadcasting) or by seeds drill.

3. Irrigation.
Crop plants absorb water from the soil by roots. Water is essential for the growth of plants. Irrigation is done by various ways like lift irrigation, water wheel, swinging baskets, sprinklers and tubewells.

4. Manuring.
Every crop uses substantial amount of nutrients present in the soil. Soil is replenished with nutrients by adding manures to it.

5. Weeding.
Many unwanted plants also germinate and grow in the field. These plants compete with the crop for water, sunlight and nutrients. Therefore, it is necessary to remove these plants to get better crops. This is called weeding.

6. Protection of Crops.
Crops are spoiled by insects, fungi, bacteria and rodents etc. Chemicals like insecticides and weedicides are used to kill them.

7. Harvesting and Storage.
When the crop is ready, it is harvested at proper time. Crops are harvested by hand, using a sickle or by a harvester. The grains are separated from the chaff in the harvested plant. Then the grains are stored in big store houses. The amount of moisture in the grains should not be more than 14%.

Question 2.
What are the practices adopted to improve crop production ?
Answer:
The practices adopted to improve crop production are as follows:
1. Addition of fertilizers to the soil.
2. Selective breeding.
3. Weed control.
4. Control of plant diseases.

1. Fertilizers.
These are the chemical compounds which are added to the soil to increase the fertility. They make up for the deficiency of the required nutrients and help in increasing the crop production.

2. Selective Breeding.
Disease resistant seeds are produced by selective breeding. Regular use of high yield variety results in better crop production.

3. Weed Control.
The unwanted plants or weeds are controlled by using certain chemicals called weedicides.

4. Control of Plant Diseases.
Crops should be protected from insects, fungi, animals and other diseases. It is very useful practice for increasing crop production. Insects are very harmful to crops. So insecticides should be used to kill insects.

Question 3.
What are fertilizers ? What are mixed fertilizers ? Why do farmers add fertilizer to the soil ? How should we store fertilizers ?
Answer:
Fertilizers. Fertilizers are the chemical substances which maintain the fertility of soil.

Mixed Fertilizers. The fertilizers which supply many elements are known as mixed fertilizers.
Example.
1. NPK has nitrogen, phosphorus and potassium.
2. CAN is a mixed fertilizer of calcium, ammonium, nitrate.

Importance of Fertilizers.
The fertilizers and mixed fertilizers are added to the soil to make up for the deficiency for mineral elements like nitrogen, phosphorus and potassium. This deficiency is produced in the soil by growing the crops in succession. That is why farmers add fertilizers to the soil to improve crop-production.

Storing of Fertilizers.
Some fertilizers are moisture lover i.e. they are hygroscopic. If the fertilizers are stored in moist places, it is difficult to apply them in the fields. Some fertilizers spoil the bags in which they are stored. They should be stored in dry places.

Question 4.
Explain the various tools used for ploughing.
Answer:
Main tools used for ploughing. The tools used for ploughing are plough, hoe and cultivator.

1. Plough.
This is being used for tilling of soil, adding fertilizers to the crop, removing the weeds, scrapping of soil, etc. It is made of wood and drawn by a pair of bulls. It contains a strong triangular iron strip called ploughshare. The main part of the plough is a long log of wood which is called a plough shaft. There is a handle on one end. The other end is attached to a beam which is hung on the neck of bulls. One pair of bulls and a man can easily operate the plough.
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 19

2. Hoe.
Hoe is a simple tool which is used for removing weeds and for loosening the soil. It has a long rod of wood or iron. A strong, broad and bent plate of iron is fixed to one of its ends and works like a blade. The other end of plough shaft is pulled by a pair of bulls.
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 20

3. Cultivator.
Nowadays ploughing is done by tractor driven cultivator. Cultivator saves labour and time.
PSEB 8th Class Science Solutions Chapter 1 Crop Production and Management 21

PSEB 8th Class Social Science Solutions Chapter 8 Disaster Management

by

Punjab State Board PSEB 8th Class Social Science Book Solutions Geography Chapter 8 Disaster Management Textbook Exercise Questions and Answers.

PSEB Solutions for Class 8 Social Science Geography Chapter 8 Disaster Management

SST Guide for Class 8 PSEB Disaster Management Textbook Questions and Answers

I. Answer the following questions in 1-15 words:

Question 1.
What is meant by the disasters?
Answer:
Any natural or man-made happening that causes loss of life and property in a region is called a disaster.

Question 2.
What are the main natural disasters?
Answer:
Earthquakes, volcanoes, tsunamis, floods, drought, cyclones, landslides, and icebergs slide.

Question 3.
What is included in the subject of Disaster Management?
Answer:
Disaster Management includes steps to reduce the damage from disasters. It includes :

  1. Preparedness before disaster
  2. Protection at the time of disaster
  3. To maintain the social life after disaster.

Question 4.
What is an earthquake? How is it measured?
Answer:
The sudden shaking of part of the earth is called an earthquake. Its intensity is measured on Richter Scale. This instrument is called Seismograph.

Question 5.
What is a volcano? Write its types.
Answer:
The interior of earth consists of hot magma. It comes out of the earth through openings. It is called a volcano. It has three types:

  1. Active
  2. Dormant
  3. Extinct volcanoes.

PSEB 8th Class Social Science Solutions Chapter 8 Disaster Management

Question 6.
How does the Tsunamis originate?
Answer:
Tsunamis are high tidal waves. These are caused due to sub-marine earthquakes. These are very destructive.

Question 7.
What are the main causes of floods?
Answer:

  1. Heavy rainfall
  2. Cyclones
  3. Cloud burst
  4. Absence of proper drainage
  5. Dam burst
  6. Deposition on river beds,
  7. Settlements in the river course.

Question 8.
What is a cyclone? By what other names is it called?
Answer:
Cyclones are violent wind system with a wind velocity of more than 63 km per hour. These are called hurricanes in North America, Typhoons in S.E. Asia and Depressions in India.

Question 9.
What can be the cause of Landslides?
Answer:
Landslides are caused due to :

  1. Internal forces of earth
  2. Heavy rainfall
  3. Volcanic activity
  4. Mining.

Question 10.
What do you mean by human disasters?
Answer:
Human disasters are related with human activities. Bomb-blasts and Terrorism are its examples.

Question 11.
What do you understand from the term ‘epidemic’?
Answer:
When a disease breaks out on a large scale and attacks people, it is called an epidemic. Dysentery, Dengu, Yellow fever, Cholera are called epidemics.

II. Answer the following questions in 50-60 words :

Question 1.
How do the disasters affect man?
Answer:
Disasters affect man in the following ways :

  • There is a loss of life and property.
  • The civic facilities are disrupted and disturbed.
  • People get separated from their families.
  • Crops and cattle are swept away.
  • Epidemics break out due to decayed corpses.
  • Progress made in years is destroyed in minutes.

PSEB 8th Class Social Science Solutions Chapter 8 Disaster Management

Question 2.
Mention causes of earthquakes and the major earthquake regions of the world.
Answer:
Earthquakes are caused due to internal movements. Tectonic plates drift and earthquake waves are caused. The earth shakes and an earthquake occurs.
PSEB 8th Class Social Science Solutions Chapter 8 Disaster Management 1
Zones :

  • About 2/3 of earthquakes occurs in Ring of Fire along Pacific coast.
  • Earthquakes occur in Himalayas and Alps.
  • In India, Jammu & Kashmir, Western Himalayas, Central Himachal, N.E. India, Ganga- Sutlej plain, Rajasthan, Gujarat and group of islands are earthquake zones.

Question 3.
Which precautions should be taken into consideration at the time of the earthquake?
Answer:
The suitable measures to be taken to protect oneself from the damage caused by earthquakes are :

  • Earthquake-resistant buildings need to be constructed in both the highest and high-risk zone areas.
  • The buildings should be flexible and strong.
  • The building plan should have the building codes which have been prescribed.
  • Existing buildings which are not earthquake resistant must be strengthened structurally.
  • Even individuals should be taught how to protect themselves during an earthquake in schools and colleges by giving them daily drills about it.
  • There should be no confusion and fear.
  • People should nor rush out.
  • People should help the victims.

Question 4.
What protective measures should be taken to save ourselves from Volcanoes and Tsunamis?
Answer:
Safety from Volcanoes:

  • There should be no building near volcanq.es.
  • Move away from a volcanic area. Use fast means of transport.
  • Govt, should be prepared for every help.

Safety from Tsunami:

  • Do not go towards sea when you come to know about Tsunami.
  • The boats and ships should return to coast.
  • Fishermen should go into the ocean only when waves are subdued.
  • If the Tsunami waves travel with a high velocity, people should leave the coastal area.
  • All should help the victims.
  • Govt should make prepared to meet any emergency.

PSEB 8th Class Social Science Solutions Chapter 8 Disaster Management

Question 5.
Which (steps) should be taken for protection from droughts?
Answer:

  • Water resources should be properly used.
  • Harvesting of rainwater must be popularised among the people.
  • Small dams for collecting water should be built.
  • Trees should be grown.
  • Farmers should be encouraged to join crops and insurance schemes.
  • Such crops should be grown which need small amount of water.
  • Water from other areas be supplied.
  • Water should be collected in tanks.

Question 6.
Which measures can save us from disasters like epidemics?
Answer:

  • The best way to save one self from epidemics is to save oneself from disasters; pure water and clear environment helps one in it.
  • Proper medical help be provided. There should be treatment facilities in Hospitals.
  • Slums should not develop near towns.
  • Regular medical check up be done in schools, villages and towns.

III. Answer the following questions in about 125-130 words :

Question 1.
Which protective measures should we adopt to save ourselves from disasters like floods and cyclones? Write in detail.
Answer:
Floods:

  • To avoid residing on river banks and slopes on riversides and the sides of gorges.
  • To build at least 250 meters away from the sea coast/river banks.
  • To provide a proper, drainage system in all flood prone areas, so that the water can be drained off quickly to prevent accumulation.
  • To construct the building with a plinth level higher than the known high flood level.
  • To construct the whole village or settlement on a raised platform higher than the high flood level.
  • To construct buildings on stilts or columns with wall-free space at ground level.
  • People should get weather forecasting from the meteorological deptt. from time to time.

Cyclones:

  • Huts and houses should not be built near coastal areas.
  • People should be shifted to schools, buildings
  • Fishermen, sailors, ships should not go into oceans.
  • Strong wind-resistant houses be built.
  • Flood control measures be taken.
  • Trees should be planted to check winds.
  • Govt, should provide information about the coming of cyclones.

PSEB 8th Class Social Science Solutions Chapter 8 Disaster Management

Question 2.
What are human disasters? Explain the disaster management of any two human disasters in detail.
Answer:
Human disasters are related to human activities and industries—man causes these unintentionally. Bomb explosion, terrorist attacks and dam burst are examples.
1. Bomb explosion and Terrorist attack. Bombs are made to be used during war. But some people cause confusion and fear among people by bomb explosion. Many innocent people die and mostly hurt. These hinder the development of a country. On 11 September, 2001 Bomb attacks were made in New York on World Trade Tower buildings.

Precautions during a Bomb Scare

  • Do not touch any doubtful packet.
  • Beware of the objects that are left on their own in public areas: suitcases, boxes, packages, etc.
  • Do not approach the objects yourself.
  • Do not allow people to touch doubtful articles.
  • Inform the police and after their arrival leave the area.
  • Avoid panic.

2. Dam Burst: Dams are used to store water. When a dam bursts, serious damage is done. In case of a big dam, it becomes a disaster. Life is disrupted. Cattle and crops are swept away. Flood control measures be used. Special precautions be used to save life and property.

IV. Activity

Question 1.
Prepare a report of 3-4 pages on natural disaster faced by India in Uttarakhand in June 2013.
Answer:
The recent flash floods in Uttarakhand have caused huge damages.

Torrential Rainfall. The torrential rainfall in the Uttarakhand Himalayas of June, 2013 resulted into huge death and destruction. It left hundreds dead; thousand marooned and washed away scores of villages, inundated the eight century Kedarnath temple. The famous Manikarinika tfemple on the banks of Bhagirathi was swept away by swirling waters of the river. Houses and small apartment blocks on the banks of Bhagirathi, Alaknanda and Mandakini have been toppled into the rushing, swollen waters and been swept away along with cars and trucks.

The extent of damage due to flash floods in many parts of the seven districts of Uttarakhand is mind-numbing. Single-story houses simply disappeared, many double-storey houses crumbled due to the weakening of its foundation. The disaster stuck when the Chardham Yatra was going on with congregation of around 75,000 pilgrims from all over the country. The Central Government, along with Indian Army, Indian Air Force (IAF), Indo-Tibetan Border Police (ITBP) and Border Road Organisation (BRO) rescued around 33,000 stranded pilgrims, The flooding was so fierce and disastrous that people named it Himalayan Tsunami.

A Man-Made Disaster. Many environmentalists termed this event as a man-made disaster. According to them human action leading to environmental altercations aggravated the problem and reduced the natural defense system. In the last three decades the region has witnessed demographic changes, deforestation, rapid urbanisation and expansion of roads. The environmentalists emphasised that mountains have a certain carrying capacity that should never be exceeded at any cost. Uttarakhand and Himachal Pradesh are the two Himalayan states that were worst hit by monsoonal flash floods in June 2013. Man-made factors compounded the scale of the disaster.

Unabated expansion of hydroelectricity power projects and construction of roads to accommodate ever increasing tourism, specially religious tourism, are the main reasons of unprecedented devastation. Mindless illegal construction of resorts, guest house, roads has taken place in this ecoSgically fragile region to accommodate tourists. Buildings have been constructed over flood ways, old drains and streams blocking the natural pathway of the water. On June 15-16, 2013, the Alaknanda River and its tributary Mandakini occupied their flood ways and started flowing along the old courses where human habitation has come up with the passage of time.

The Mandakini changed its course to the west. The sediment-loaded river washed away shops, guest houses/lodges etc., killing people who were present at the time.

Kedarnath Dham, a place of serenity and devotion, which was dotted by only few huts in 1882 was mushroomed by haphazard illegal constructions of buildings, shops, hotels/ lodges etc,, blocking the natural flow of the Alaknanda river.

Ganga and its tributaries like Alaknanda, Mandakini, Bhagirathi, Kali Ganga, Gauri Ganga, were swept away or excessively damaged due to flash floods.

Due to increased anthropogenic activities and terrain instability, Uttarakhand had always remained prone to landslides. Even during August and September 2010, Uttarakhand. Himalayas witnessed large scale slope destabilisation.

The June, 2013 Uttarakhand disaster, also known as Himalayan Tsunami was actually triggered by very heavy rainfall during June 16-18 and unusual behaviour of monsoon this year in India.

Rainfall measurement for June 16 and 17, 2013, at the Dehradun station was 220 millimeters and 370 millimeters respectively. It Indicates the severity of the rainfall. Haridwar received 107 mm and 218 mm of rainfall in two days. Uttarkashi received 122 mm and 207 mm. While Mukteshwar (at the altitude of 2000 m) received 237 mm and 183 mm respectively on June 17 and 18, Nainital, on the very same day, received 170 mm rainfall.

Rescue Work:
It was the army personnel who worked tirelessly and put their lives in danger to help and rescue stranded lbcals and pilgrims affected by flash floods. They provided people essential materials such as food, blankets and medicines. The Indian Air Force (IAF) put to use some of the best military skills to help people in flood ravaged zones of Uttarakhand and rescued hundreds of fatigued and exhausted, stranded pilgrims and locals. Operation ‘Rahat’ was the biggest ever helicopter based rescue operation in history. 45 choppers made sorties day in and day out despite bad weather and hazardous conditions. It mobilized the resources, evacuated people to relief and base camps and carried out extensive search and rescue operations creating a world record. The unusual advance of summer monsoon, combined with cloudbursts (still not confirmed) and geophysical dynamics (loose soil, landslides and lake bursts) had channeled huge devastation through massive flash flooding in Uttarakhand, which turned into a major disaster due to the combined impact of anthropogenic activities and breaching of the carrying capacity due to irresponsible tourism.

PSEB 8th Class Social Science Guide Disaster Management Important Questions and Answers

Multiple Choice Questions :

Question 1.
Which one of the following is not a zone of high earthquake intensity?
(a) N.E. India
(b) Gujarat
(c) the Himalayas
(d) Haryana
Answer:
(d) Haryana.

PSEB 8th Class Social Science Solutions Chapter 8 Disaster Management

Question 2.
Which temple was affected by the Uttarakhand disaster?
(a) Kedarnath temple
(b) Sun temple
(c) Mandakani temple
(d) Vaishno Devi temple.
Answer:
(a) Kedarnath temple.

Question 3.
On which scale shows damage done by earthquake?
(a) Richter scale
(b) Marcoli scale
(c) Ritcher scale
(d) None of the above.
Answer:
(b) Marcoli scale.

Question 4.
When was World Trade Centre attacked?
(a) 12 ,Sept. 2011
(b) 11, Sept. 2001
(c) 12, Sept. 2001
(d) 13, Sept. 2001.
Answer:
(b) 11, Sept. 2001.

Question 5.
Which one of the following Disaster Management Institute not in Delhi?
(a) Indira Gandhi Open University
(b) Central Board of Secondary Education
(c) Disaster Management National Centre
(d) Disaster Management Institute.
Answer:
(d) Disaster Management Institute.

Question 6.
Look at the following picture and write the name of the disaster shown in the picture.
PSEB 8th Class Social Science Solutions Chapter 8 Disaster Management 2
(a) Earthquake
(b) Floods
(c) Cyclones
(d) Accident.
Answer:
(b) Floods.

Question 6.
On 26th December, 2004 Maninder went to the seashore with his parents to enjoy. Suddenly high waves started appearing in the sea. What should they do in this situation?
(a) They shout loudly.
(b) They need to stand under a tree.
(c) Stay at the same place.
(d) Move away from the sea to a secure place.
Answer:
(d) Move away from the sea to a secure place.

Question 7.
You are having a class test. Suddenly the fans and the doors of the room start shaking. Tell What type of natural disaster is it?
(a) Droughts
(b) Earthquake
(c) Floods
(d) None of these
Answer:

Fill in the Blanks:

Question 1.
_________ hazard does not occur frequently.
Answer:
Natural

Question 2.
Earthquake information centre, I.I.T. is in _________
Answer:
Kanpur

PSEB 8th Class Social Science Solutions Chapter 8 Disaster Management

Question 3.
_________ is the cause of road accidents.
Answer:
Drunk driving

Question 4.
Volcano is a _________ in the earth’s crust through which molten rocks out to the surface of the earth.
Answer:
vent

Question 5.
_________ are sliding mass of rocks down the slope.
Answer:
Landslides.

True/False :

Question 1.
Bomb explosions are natural resources.
Answer:
False

Question 2.
Dams are used to store water.
Answer:
True.

Question 3.
Hits and houses should not be built near coastal areas.
Answer:
True.

Question 4.
On intensity Richter scale-7 earthquakes are considered dangerous.
Answer:
False

PSEB 8th Class Social Science Solutions Chapter 8 Disaster Management

Question 5.
Alaknanda and Mandakani are two river which are overflowed.
Answer:
True.

Very Short Answer Type Questions

Question 1.
What are the ill-effects of a disaster?
Answer:
Loss of life, property and cause damage to a large number of people.

Question 2.
Which intensity, earthquakes are considered dangerous?
Answer:
On Richter Scale-8.

Question 3.
On which two buildings was a major Terrorist attack made in U.SA?
Answer:
On 11 Sept., 2001 in New York-Tower buildings and Pentagon.

Question 4.
Define Focus and Epicentre.
Answer:
Focus is the origin of Earthquake waves, Epicentre is the place on the surface of the earth directly above focus.

PSEB 8th Class Social Science Solutions Chapter 8 Disaster Management

Question 5.
What damage is done due to earthquake?
Answer:

  1. Cracks appear in buildings. Houses, roads, bridges, railways are disrupted. People die.
  2. Water, gas, electricity supply is closed.

Question 6.
On 26th December, 2004. How many countries were affected by Tsunamis? How many people were killed?
Answer:
11 countries of Asia and Africa were affected by Tsunami. About 10 lakh people were killed

Question 7.
What is a flood?
Answer:
When the river water spreads beyond its bank it is called a flood.

Question 8.
What are cyclones and tropical cyclones? How are these caused?
Answer:
Cyclones are whirlwind of high speed winds. Their velocity is more than 63 km per hour. These are caused due to pressure. These mostly occur between 5°-206 latitudes

Question 9.
What is a drought?
Answer:

  1. It is prolonged period of dry weather in a region, where some rain might be expected.
  2. Droughts last for years.
  3. They are caused because of changes in climate and human activities.
  4. It leads to acute shortage of water, food and fodder.

Question 10.
Which temple was affected by the Uttarakhand disaster?
Answer:
Kedamath temple.

Question 11.
Name the two rivers which overflowed.
Answer:
Alaknanda and Mandakani.

PSEB 8th Class Social Science Solutions Chapter 8 Disaster Management

Question 12.
Name a major chemical disaster which occurred in India.
Answer:
Bhopal Gas tragedy.

Question 13.
According to the device that measures the intensity of earthquake, 12 means complete destruction. What is this device called?
Answer:
Richter Scale.

Short Answer Type Questions

Question 1.
Distinguish between Richter scale and Marcoli scale.
Answer:
Richter Scale. It is a scale used to measure intensity of earthquakes. It shows intensity of tremors on Richter scale, an earthquake with intensity of 8 is considered dangerous.
Marcoli scale shows damage done by earthquakes. It shows 0 to 12 as the damage increases.

Question 2.
Name the different type of volcanoes.
Answer:
Types of volcanoes
1. Active volcanoes. The volcanoes that erupt frequently and are always emitting lava are called active volcanoes. Mauna Loa in Hawaii is islands the largest active volcano in the world. There are about 150 active volcanoes in the world.

2. Dormant volcanoes. Dormant volcanoes are also called sleeping volcanoes. These volcanoes have been active in the past; stopped ejecting lava now, but can erupt any time. The Vesuvius of Italy is such a dormant volcano.

3. Extinct volcanoes. The volcanoes which have never erupted in human history are called extinct or dead volcanoes, such as Kilimanjaro in Africa.

PSEB 8th Class Social Science Solutions Chapter 8 Disaster Management

Question 3.
How do cyclones become a disaster? Describe the damage done by these.
Answer:
In a cyclone, when winds move with a velocity of 100 kms per hour it becomes a disaster. These damage the adjoining areas.

Damages:

  1. They are intense storms that develop over warm and tropical oceans between 5° and 20° North and South of Equator.
  2. The velocity of winds exceeds 10 km per hour which cause large-scale destruction in its path.
  3. The crops are damaged, trees are uprooted.
  4. They destroy telephone and electricity lines.
  5. They blow away weak structures like; roofs, etc.
  6. It also destroys houses and other settlements which effects human lives

Question 4.
Describe the disaster and precautions for Dam Burst.
Answer:
Dams are used for reservoirs to store more water. Dam burst causes floods. When there is a big dam, it is a disaster. Whole life is disrupted. Govt, should take measures to save life and property.

Question 5.
What do you know about disaster caused by Industrial accidents?
Answer:
Industries have big machines and plants. Many gases are used in these. Sometimes accidents occur due to leakage of gases like Bhopal Gas Tragedy. There ill-effects are :

  • The fire causes huge loss of life and property
  • Temperature increases
  • Poisonous gases kill people
  • Various respiratory diseases spread
  • People become unemployed
  • Environment is degraded.

PSEB 8th Class Social Science Solutions Chapter 8 Disaster Management

Question 6.
What measures are taken for safety during industrial accidents?
Answer:
The following precautions should be taken against fire:

  • Do not keep flammable liquids in the house.
  • In case of fire, the evacuation route should be used.
  • Install a fire extinguisher on a wall in your house.
  • All electrical and gas appliances should be shut when you are going out of the house.
  • Do not create a panic.

Long Answer Type Question

Question 1.
Describe the disasters caused due to landslides and avalanches. Suggest measures to reduce the risk.
Answer:
Landslides. Groundwater increases the weight of the rock or the soil which contains it. Sometimes a mass of earth saturated with water slides down a hill slope causing landslides.

Causes: One or more causes such as lubrication by rains or melting snow, steep slopes and unusual structures, earthquakes, removal of support, or gravity may produce landslides. Lubrication of rocks takes place by means of rains or melting snows as in many parts of the Himalayas. Rocks become slippery and slide down. Steep slopes may be caused by the sliding of rocks straight through faulting or by quarries made by man. The sides of these may collapse on accounts of other factors.

Effects of landslides. Landslides and rock slides are of frequent occurrence in many mountains. National highways are closed. Cattle and vehicles suffer a lot.

Measures to reduce the risk during the landslides :

  • Cutting down of trees must be stopped on mountain slopes.
  • Avoiding construction of buildings on steep slopes.
  • Building codes have to be followed strictly.
  • Drainage should be proper.
  • Afforestation on slopes is done.
  • Retaining walls along roads are built.

Avalanches: The. sliding of ice along the slope leads to avalanches downwards. These cause a lot of damage to roads, cattle, human beings, buildings, etc. When the pressure of ice increases, it slides down the slopes.

Measures:

  • Knowledge of avalanches is provided to people.
  • Afforestation can check it.
  • Barriers should be built to check the movement of avalanches.
  • Ice-breaking machines are used to clear ice on roads.
  • Relief is given to victims.

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

by

Punjab State Board PSEB 8th Class Social Science Book Solutions Geography Chapter 4 Our Agriculture Textbook Exercise Questions and Answers.

PSEB Solutions for Class 8 Social Science Geography Chapter 4 Our Agriculture

SST Guide for Class 8 PSEB Our Agriculture Textbook Questions and Answers

I. Answer the following questions in 1-15 words:

Question 1.
What do you understand by Agriculture?
Answer:
Agriculture includes raising crops, cattle rearing, and other agricultural activities. It also includes dairy farming, poultry, bee-hiving, fishing, floriculture, gur production, flour mills, etc.

Question 2.
Which factors affect Agriculture?
Answer:
The following factors affect agriculture:

  1. Climate
  2. Relief
  3. Type of soil
  4. Irrigation
  5. Method of cultivation
  6. Marketing
  7. Means of transportation and
  8. Banking facilities.

Question 3.
Write a brief note on plantation farming.
Answer:
It includes the cultivation of single crop on large farms.

Question 4.
Write the names of cereal crops.
Answer:
Main cereal crops are Rice, Wheat, Maize, Jowar, Bajra, Pulses and Oilseeds.

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

Question 5.
What is puddling?
Answer:
For rice cultivation, seeds are planted in the fields. The field is levelled and filled with water. This is called puddling the field where rice plants are transplanted.

Question 6.
What products are prepared from Maize?
Answer:
Glucose, starch, alcohol and vegetable oil is prepared from Maize.

Question 7.
How many types of cotton are there on the basis of the length of staple?
Answer:

  1. Long staple cotton (Best Type)
  2. Medium staple cotton
  3. Short staple cotton.

Question 8.
Which are the things that can be made from jute?
Answer:
Bags, ropes, strings, etc. and shoes are prepared from jute.

Question 9.
How does the tea plant look like?
Answer:
Tea plant is a bush. Its leaves provide tea.

Question 10.
Write the names of three types of coffee.
Answer:

  1. Arabica
  2. Robusta
  3. Liberica.

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

Question 11.
What is the percentage of people engaged in agriculture in U.S.A. and Punjab?
Answer:

  • U.S.A.-More than 30% people
  • Punjab-58% people.

II. Answer the following questions in 50-60 words :

Question 1.
After writing the types of Agriculture differentiate between intensive and extensive agriculture.
Answer:
Types of Agriculture :

  1. Sedentary Agriculture
  2. Shifting Agriculture
  3. Dry Farming
  4. Wet Farming
  5. Intensive Farming
  6. Extensive Farming
  7. Mixed Farming
  8. Horticulture
  9. Individual Agriculture
  10. Co-operative Farming
  11. Collective Farming
  12. Plantation Agriculture
  13. Subsistence Agriculture
  14. Commercial Farming.

The distinction between Intensive and Extensive Farming :

  • Intensive farming is done on small farms while extensive farming is done on large farms.
  • Irrigation and fertilizers are used in intensive farming while machines are used in extensive farming.
  • Intensive farming is done in Punjab while extensive farming is done in U.S.A.

Question 2.
Differentiate between subsistence and commercial type of farming.
Answer:
1. Subsistence Farming: Majority of farmers in the country practise subsistence farming. It is characterised by small and scattered land-holdings and use of primitive tools. As the farmers are poor, they do not use fertilisers and high yielding variety of seeds in their fields to the extent they should do. These result into low productivity. Important cash crops like sugarcane, oilseeds, cotton and jute are grown. The subsistence agriculture has given way to commercial agriculture to some extent.

2. Extensive Farming: Extensive farming is bush or tree farming. It is a single crop farming of rubber, tea, coffee, cocoa, spices, coconut and fruit crops. It is capital-intensive and demands good managerial ability, technical know-how, sophisticated machinery, fertilisers, irrigation and transport facilities. Extensive farming is done in U.S.A. and Canada.

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

Question 3.
Which are main Rice producing areas?
Answer:
Cultivation of Rice. Rice is grown in deltas, flood-plains, coastal-plains and some terraced fields in the mountainous areas as well. It is one of the crops for which a lot of human labour is required. All operations including the preparation of seedling beds, ploughing, planting, weeding, harvesting and separation of grain are done by human labour.

Rice requires high temperature of over 20°C to germinate, bloom and mature. Rainfall of 100 cm to 150 cm is required. Paddy is cultivated mainly in India, China, Japan, Bangladesh, Indonesia, Thailand and Myanmar.

In India rice is cultivated most widely in Uttar Pradesh, West Bengal and Andhra Pradesh. Other producers are Assam, Tamil Nadu, Orissa and Punjab.

In Punjab, rice is grown in districts of Amritsar, Gurdaspur, Ferozepur, Jalandhar, Patiala and Ludhiana.

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture 1

Question 4.
Explain the conditions required for cultivation of cotton and jute.
Answer:
Cotton. Cotton requires cloud free sunny days and uniformly high temperature. It grows best in areas where the temperature is between 30°C to. 40°C. Cotton plants require rainfall of 60 to 100 cm. Alluvial and black soils are best suited for cotton plants.

Jute. Jute fibre is obtained from the bark of the jute plant stem.
The jute plant originated in the Indian subcontinent. It grows best in well drained sandy loam and requires warm and humid climate. Jute plant requires temperature of more than 25°C and rainfall of over 150 cm per year.

Question 5.
Write a note on cotton production in Punjab.
Answer:
Punjab and Haryana together produce 25% cotton of India. The major producers are Ferozepur and Sangrur districts. B.T. cotton has been successfully grown in Punjab. Malwa region is also called white gold.

Question 6.
Write about protection of tea and coffee plants.
Answer:
Tea. Tea plants are planted on cleared slope. So that on well drained slopes, water should not stand in the roots of plants. Fertilizers are used for growth of tea plants. Tea plant needs pruning for its proper growth.

Coffee. Coffee saplings are grown in Nursery and then transplanted in the fields. The plants require use of fertilizers, pruning, and irrigation. Sunny weather is required during growth. The tree is pruned to keep it upto a height of 8 feet.

Question 7.
Write a note on the uses of machines in agricultural operations in U.SA.
Answer:
Two types of farms are functioning in the United States viz.,

  1. specialized farms and
  2. mixed farms.

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture 2

A specialized farm concentrates on a particular type of crop or livestock, whereas a mixed farm raises a variety of crops. About 95 per cent of farms in the USA are specialized farms. Mostly cereal grains such as corn, wheat, sorghum, rice, barley, oats and rye are grown in specialized farms. However, specialized farms also produce crops such as cotton, groundnut, sugarcane, tobacco, vegetables and fruits. Nearly half the specialized farms in the USA are livestock farms. These livestock farms rear meat animals, raise milk cows, chickens and turkeys. In the mixed farms, farmers produce a variety of crops and rear livestock. The United States is the world’s leader in international agricultural goods market.

III. Answer the following questions in about 125-130 words :

Question 1.
After writing about conditions for the growth of wheat explain the areas of wheat production. (P.B. 2009)
Answer:
Geographical conditions of growth. Wheat needs a cool and wet climate during growing season and a warm dry climate during harvesting season. It requires a rainfall of 50 cm to 75 cm. It is a rabi crop. It grows best in winter due to winter rainfall and regular irrigation. It does not depend on destiny like rice crop. Wheat grows best on loamy soils. Mechanisation and use of chemical fertilizers give higher yields.

Production. Wheat is one of the oldest cereal crops cultivated in the world. Wheat is grown in temperate regions with rainfall ranging between 30 cm to 80 cm.

Three countries: the United States of America, Russia and China are the major producers of wheat. The world’s largest producer is China. Other leading producers are India, Ukraine, France, Canada, Pakistan and Argentina. Winter wheat and spring wheat belts of USA and Canada are quite famous.

Wheat cultivation is mainly carried on in fertile soils or loamy soils. Different climatic conditions and sowing seasons across the world have led to harvesting of wheat in every month of the year in one or the other part of the world. It is grown in Punjab, Haryana, Uttar Pradesh, Madhya Pradesh, Maharashtra and Bihar. India is the second largest producer of wheat in the world. The production and yield in Punjab has increased due to Green Revolution, Better seeds, fertilizers and irrigation is used. ,

Question 2.
What are the conditions required for the growth of Tea and Coffee? Explain the main areas of tea and coffee production in India.
Answer:
Geographical Conditions of Growth of Tea. Tea is a plant of both tropical and temperate areas.

  1. Temperature. Tea requires uniformly high temperatures (20° – 30°C) throughout the year. Frost is harmful for tea leaves.
  2. Rainfall. An annual rainfall of 150 cm is essential for the growth of tea.
  3. Soil. Tea requires a deep acidic and fertile soil.
  4. Land. Tea is grown on gently sloping, well drained hill slopes and valley-sides.
  5. Labour. Tea is a labour intensive crop. It requires cheap, skilled labour for picking tea-leaves.

Conditions for Growth of Coffee. One-third of the world population drinks coffee, the second largest beverage after tea. There are two types of coffee plants. Coffee Arabica or Mocha and Coffee Robusta. Robusta is the main variety produced in the world.

The coffee plant requires warm climate and moderate rainfall. Both strong sunshine and snowfall are harmful to the plant. During its growth, coffee plant requires rainfall of 100 cm to 150 cm and temperatures between 15°C and 25°C. Irrigation is required where the annual rainfall is less than 100 cm.

Areas of Cultivation of Tea. More tea is produced in Northern India than Southern India. Tea is grown on an area of 4.21 lakh hectares.

The average yield is 1540 kg per hectare. Assam produces about 50% tea of India.
1. Assam. Assam is the largest producer of tea in India. Tea is grown on the valley sides of Brahmaputra and Duar region.
PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture 3

2. West Bengal. Tea is grown in Darjeeling and Jalpaiguri districts in West Bengal. Darjeeling tea has a special flavour. This flavour is due to slow growth under high humidity and low temperature.

3. Southern India. Tea is grown on the slopes of Nilgiris, Cardamom and Anamalai hills, Coimbatore (Tamil Nadu), Malabar coast (Kerala), Coorg region (Karnataka) and Ratnagiri (Maharashtra) are important areas of tea production. Areas of Cultivation of Coffee.

Karnataka is the largest coffee producing state of India.
(а) Karnataka. Coffee is grown in the districts of Chikamanglur, Coorg, Hassan, Shimoga (Nilgiris) in Karnataka state. High rainfall, sunshine, protected slopes, well- drained soils favour the cultivation of coffee.
(b) Arcot, Tinevelley, Madurai, Coimbatore districts of Tamil Nadu grow coffee.
(c) In Kerala, Cardamom hills covering the districts of Palghat and Thiruvananthapuram.

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

Question 3.
Write down the process involved in Jute production. Write in detail the uses and distribution of Jute in the world.
Answer:
Jute: Jute is an industrial fibre. It is the cheapest fibre. It has commercial importance. It is also called ‘golden fibre’. It is used in the making of carpets, ropes, covers and linoleum. It is used for packing many agricultural commodities. Jute is called ‘Brown Paper of Whole-sale trade’. Jute fibre has softness, strength and length.

Conditions of Growth: Jute is a plant of hot-wet tropical areas.

  1. Temperature. It requires uniformly high temperature (27°C) throughout the year.
  2. Rainfall. Jute requires well distributed heavy rainfall (150 cm).
  3. Soil. It is grown on flood plains and deltas. Fertilizers are also used.
  4. Clean Water. Jute needs an ample supply of clean water for washing.

Area and Production: The jute is grown on an area of about 8 lakh hectares. The total production is about 93 lakh bales (each bale = 180 kg). The average yield is 2014 kg per hectare.

India is the largest producer of jute in the world. Due to partition of India 75% of jute producing areas remained in East Pakistan (now Bangladesh). There was shortage of raw jute for jute mills in India. Now India is self-sufficient in jute production. Coarse jute called Mesta is also grown.

Areas of Cultivation

  1. West Bengal. West Bengal is the largest producer of jute in India. Jute is grown in Ganges delta. Murshidabad, Burdwan, Nadiad, Hooghly are the main jute producing districts.
  2. Assam. Jute is grown in Goalpara, Kamrup and Tezpur districts in Brahmaputra valley.
  3. Bihar. Jute is grown in Terai districts of Purnea and Champaran. The major producers of Jute in the world are China, India, Bangladesh, Thailand and Brazil.

Question 4.
What are the similarities and variations in the agriculture of Punjab and the U.S.A.?
Answer:
(A) Agriculture in the U.S.A.-A Glance :

  • Agriculturally, the U.S.A. is a developed country. About 3% of the total population is engaged in agriculture,
  • The main reason behind this is that all the activities of agriculture are carried on by machines and. not by men.
  • Agricultural activities are carried on about 20% part of the land,
  • The main agricultural areas include North-West, North-East, interior plains and coastal plains of the country. Different types of crops are grown in different parts of the country,
  • The farmers of the U.S.A. have large landholdings as compared to that of India. The farm size is very big. The average farm size in U.S.A. is 700 acres. Due to the large size of the fields, extensive type of agriculture is practised.
  • Machines are used at a very large scale. It is almost impossible to work in farms without machines,
  • In a farm, only one type of crop is cultivated. From the sowing of crop to the taking of the crop to markets or stores, every work is done with the help of machines,
  • Insecticides and pesticides are properly utilized. The farmer of U.S.A. practice agriculture like a businessman and not like a mere farmer.

(B) Agriculture in Punjab (India)-A Glance :

  • Punjab in comparison to other states of India, is much advanced in agriculture. The agriculture sector contributes 35% to the total income of the country. About 58% population of the state is engaged in agriculture,
  • The soils here are fertile in nature. To maintain the fertility of the soils, the farmer also uses fertilisers,
  • The farmers of Punjab do not have too much of land. Landholding mostly range between 5 to 25 acres. Some farmers possess even less land. Six percent farmers of the state have more than 25 acres of land.
  • The farmer grows, different types of crops in his fields. The variations in crops mainly depend on climate, size of landholding, type of soil, irrigation facilities and requirements of the farmer.
  • According to the size of the land holding the farmer uses tractor or combine harvester,
  • Almost all the net sown area comes under irrigation. The farmer of Punjab also uses insecticides and pesticides at a large scale to get more production. Though the farmer of Punjab uses the machines, even then the contribution of labourers is too much. This we can estimate from the number of people working in the agricultural sector. In U.S.A. only 3% of population is engaged in agriculture whereas in Punjab 58% people are working in the agriculture sector,
  • The farmer of Punjab (except a few big farmers) does not practice agriculture like a businessmen. He sows a number of crops in his fields. Two-2 crops are taken at the same time,
  • The agriculture of Punjab is an intensive type of agriculture. Therefore, the yield per acre is more than that of the U.S.A.

IV. Map Skill

Question 1.
Show two place’s each of following crops on outline map of India. Tea, Wheat, Rice, Cotton, Jute.
Answer:
PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture 4

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

V. Activity

Question 1.
Name three each of Kharif and Rabi crops mentioning geographical conditions need for each.
Answer:

Crop Temp Rainfall Soils
1. Wheat 10°-20°C 50-100 cm Clay soil
2. Rice 20°-30°C 100-200 cm Alluvial soil
3. Maize 18°-27°C 50-100 cm Levelled plain
4. Cotton 20°-30° 50-100 cm Simple slope
5. Tea 20°-30°C 150-300 cm Sloping
6. Jute 29°-35°C 120-150 cm Alluvial soil

PSEB 8th Class Social Science Guide Our Agriculture Important Questions and Answers

Multiple Choice Questions :

Question 1.
Commercial rearing of silkworm is called
(a) Commercial farming
(b) Pisciculture
(c) Sericulture
(d) Viticulture.
Answer:
(c) Sericulture.

Question 2.
Farming in which the produce is consumed by the farmer’s household is called :
(a) Subsistence
(b) Extensive
(c) Intensive
(d) None of the above.
Answer:
(a) Subsistence.

Question 3.
What does golden filament means?
(a) Cotton
(b) Jute
(c) Silk
(d) Wool.
Answer:
(b) Jute.

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

Question 4.
Which country is the largest producer of rice in the world?
(a) India
(b) Brazil
(c) China
(d) U.S.A.
Answer:
(c) China.

Question 5.
India is largest producer of _________
(a) Tea
(b) Coffee
(c) Rice
(d) Cotton.
Answer:
(a) Tea.

Question 6.
For what purpose the following machine is used?
PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture 5
(а) For drilling
(b) For showing wheat / rice
(c) For harvesting
(d) For growing vegetables.
Answer:
(c) For harvesting.

Question 7.
In the following picture a plant is shown, name the areas in which plant is found.
PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture 6
(а) Tropical
(b) Temperate
(c) Tropical & temperate
(d) None of these.
Answer:
(c) Tropical & Temperate.

Question 8.
What is the name of farming of fruit shown in this picture?
PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture 7
(а) Horticulture
(b) Sericulture
(c) Pisciculture
(d) Viticulture.
Answer:
(d) Viticulture.

Question 9.
Which of the following crops does this picture resemble?
PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture 8
(a) Paddy (Rice)
(b) Wheat
(c) Maize
(d) Cotton.
Answer:
(a) Paddy (Rice).

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

Question 10.
What type of crops can be grown on the part of land with plenty of black soil?
(a) Sugarcane
(b) Wheat
(c) Cotton
(d) Jute.
Answer:
(c) Cotton.

Fill in the Blanks :

Question 1.
_________ agriculture is done with machines in sparsely populated areas.
Answer:
Extensive

Question 2.
_________ is called cultivation of grapes.
Answer:
Viticulture

Question 3.
Shifting cultivation is also called _________
Answer:
Slash and burn

Question 4.
Coarse grain are also called _________
Answer:
Millets

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

Question 5.
Agricultural activity in India is a _________
Answer:
primary activity.

True/False :

Question 1.
Production of fruit and flower is called viticulture.
Answer:
False

Question 2.
Punjab state is the largest producer of wheat.
Answer:
False

Question 3.
Arabica is a variety of coffee.
Answer:
True

Question 4.
Flax is a fibre crop.
Answer:
True

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

Question 5.
Russia is a leading producer of coffee.
Answer:
False.

Very Short Answer Type Questions

Question 1.
What is meant by agriculture?
Answer:
The word ‘agriculture’ is derived from the Latin words ‘ager’ or ‘agri’ and ’culture’. Ager means soil and culture means cultivation or tilling the soil. Agriculture, thus, means cultivation of soil. But in broader sense, agriculture is growing crops and rearing of livestock. Livestock include animals (cattle, sheep and goat) and birds that are reared for human use.

Question 2.
What are the different forms of the word ‘culture’?
Answer:
The word cuture has many variants like :

  1. Agriculture. Science and art of cultivation on soil, raising crops or livestock.
  2. Sericulture. Commercial rearing of silkworms.
  3. Pisciculture. Breeding of fish for commercial gains.
  4. Viticulture. Cultivation of grapes.
  5. Horticulture. Growing of vegetables, fruits or flowers for commercial use.

Question 3.
What is Sedentary Agriculture?
Answer:
When a farmer practises settled agriculture at a fixed place, it is called sedentary agriculture. Crops can be grown every year at the same field. Organic fertilizers and chemical fertilizers are used to increase the fertility of the soil.

Question 4.
What is mixed farming?
Answer:
In mixed farming, foodgrains, fruit, vegetables are grown along with cattle farming. Fisheries and. bee-hiving is also done. It increases the income of farmers.

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

Question 5.
What is the main characteristic of plantation farming?
Answer:
Crops are grown on large farms. Tea, coffee, rubber are plantation crops which give yield for many years.

Question 6.
Enlist the fibre crops and the beverage crops.
Answer:
Fibre Crops. Cotton, jute, flax.
Beverage Crops. Tea, coffee, cocoa.

Question 7.
Why the people of rich countries prefer wheat to rice?
Answer:
Wheat contains protein, carbohydrate and vitamins. Therefore, wheat is preferred to rice.

Question 8.
State the conditions of growth, temperature, rainfall and land required for maize.
Answer:

  • Temperature: 18°C – 27°C, Frost free season.
  • Rainfall: 50 cm to 100 cm.
  • Land: Level or rolling.

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

Question 9.
What are oilseeds? What is their importance?
Answer:
The seeds which provide oil are called oilseeds. These include til, sunflower, rapeseed, etc. These provide us food and meet our daily needs.

Question 10.
Which sources provide fibre? For which purpose fibre from sheep is used?
Answer:
Fiber is obtained from plants and animals. Wool from sheep is used for woollen clothes.

Question 11.
What is the use of cotton fibre?
Answer:
Cotton fibre is used as a raw material for textile industry. It makes fight and strong clothes.

Question 12.
Explain the term ‘farm system’.
Answer:
Agriculture or farming or cultivation is s system called farm system.

  • Inputs. Include seeds, fertilisers, water, machinery, and labour.
  • Operations. Ploughing, sowing, irrigation, weeding, and harvesting.
  • Outputs. Crops, wool, dairy, products, poultry, etc.

Question 13.
Name the main states producing cotton. Account for large production in these states.
Answer:
Maharashtra, Gujarat and Andhra Pradesh produce more than 60% cotton of India. The large production is due to fertile black soils in these states.

Question 14.
Why is tea grown on hill slopes?
Answer:
Tea needs uniform supply of water throughout the year. Water should not stagnate in the roots of tea bush. Hill slopes are well-drained.

Question 15.
How is coffee powder prepared? Which element of it produces excitement in our bodies?
Answer:
Coffee seeds are dried, roasted and grinded to make powder. It contains Caffeine which produces excitement in our bodies.

Question 16.
How is coffee plant grown?
Answer:
Coffee plant is grown in nurseries. After six months, it is transplanted in fields. It starts giving fruit after 3-4 years.

Question 17.
Agricultural development is uneven in different parts. Give one example.
Answer:
Many parts of Africa are not agriculturally developed. But in U.S.A., agriculture is a commercial and profitable occupation.

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

Question 18.
What is Green Revolution?
Answer:
The increase in agricultural production by introducing scientific methods like; new varieties of seeds, use of fertilizers and good water supply is called green revolution. The increase was in the yields of certain crops like wheat and rice.

Question 19.
Which activities are included in Agriculture?
Answer:
Dairy farming, poultry, honey bee keeping, pisciculture, gur making, flour milks, floriculture all occupations are a part of agriculture.

Question 20.
State two characteristics of Extensive farming.
Answer:

  1. Size of farms is very large.
  2. Yield per acre is less and machines are used for agriculture.

Question 21.
What is the position of Punjab in production of rice?
Answer:
Per hectare yield of rice in Punjab is the highest in India. Punjab produces about 12.2 per cent of total rice of the country. Punjab ranks second in rice production.

Question 22.
If a person has cultivated crops like Tea, Coffee and Cocoa, then identify the types of these crops.
Answer:
Beverage crops.

Short Answer Type Questions

Question 1.
Discuss the main characteristics of shifting cultivation.
Answer:
Shifting Agriculture. In this type of agriculture, first of all, a piece of forest land is cleared by felling trees and burning of trunks and branches. After the land is cleared, crops are grown for two to three years and then the land is abandoned as the fertility of the soil decreases. The farmers then move to new areas and the process is repeated. Dry paddy maize, millets and vegetables are the crops commonly grown in this type of farming. The per hectare yield is low.

Question 2.
Distinguish between dry land farming and wetland farming.
Answer:
Dry land farming. It is practised in areas where the rainfall is low and irrigation facilities are inadequate. Here, emphasis is laid on the conservation of moisture and on crops like jowar, bajra and pulses, which need less water. In dry farming, only one crop is grown in the kharif season.

Wet land farming. It is practised in the areas where rainfall is more than 200 cm per year. It is mostly practised in S.E. Asia. In India, it is practised in West Bengal, Orissa and coastal areas. The main crop is Rice, Sugarcane. Multiple Cropping is done in different seasons.

Question 3.
Distinguish between Individual and Cooperative farming.
Answer:
Individual farming. In this farming, the farmer is the owner of the land. The use of tools, fertilizers and management is in the hands of the farmer. The total income is the personal income of the farmer.

Co-operative farming. In this, the Govt, is the owner of the land. A part of the income goes to the government as tax. The rest of income is divided among the labourers and farmers. This type of agriculture was practised in U.S.S.R.

Question 4.
Write a note on Collective farming.
Answer:
In this type, the farmers join together to form a collective organisation. All the farmers cultivate their own land. The accounts of production is in the hands of the organisation. The decisions are taken for the benefit of farmers. All the profit is distributed among farmers in the ratio of their lands. In India, this type of farming is encouraged by the government.

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

Question 5.
Describe the favourable conditions for growth of Rice.
Answer:

  • Temperature: 20°C to 30°C.
  • Rainfall: 100-200 cm (Irrigation in dry areas)
  • Soils: Alluvial, clay, loamy and delta or black soils.
  • Land: Level land suitable for irrigation.
  • Labour: Cheap and skilled labour.

Question 6.
Describe the cultivation of maize in India and world.
Answer:
Maize: Maize is known as Makka in India, corn in the United States of America, India and Europe. It originated from the American continent. It was introduced in Europe by Columbus and other explorers. It was Native Americans who taught colonizers how to grow maize.

Maize is used as foodgrains and as fodder. It is grown mainly in Russia, Canada and parts of South America. The United States of America is the largest producer. China is the second-largest producer followed by Brazil, Mexico, Argentina and India.

India: Most of Maize is grown in Madhya Pradesh, Andhra Pradesh, Karnataka and Rajasthan. U.P, Himachal Pradesh, J & K, Maharashtra, Punjab and Gujarat are also the producers of Maize. In Punjab, Rupnagar, Amritsar, Hoshiarpur, Jalandhar produce maize.

Question 7.
Write a note on the agricultural development of Punjab.
Answer:
Punjab is one of the leading states of India in agriculture. This is due to :

  • 58% people are engaged in agriculture. 35% of income comes from agriculture.
  • Soils are fertile. Fertilizers are used.
  • Mulitple cropping is done. Better seeds are used. Tractors and Harvesters are used.
  • Irrigation is the basis of agriculture.
  • Pesticides are used to protect crops.
  • Machines are used on large farms.

Question 8.
Why agriculture is called the main stay of the Indian Economy?
Answer:
Indian’s main occupation is agriculture. Two-thirds of India’s population is engaged in agriculture. Agriculture is the main stay of the Indian Economy. Agriculture provides food to the teeming millions in India. It sustains 2/3 of our population. It provides raw material to agro-based industries. Agriculture along with forests and fisheries form 45% of our total national income. Our industrial structure is being built on the broad foundation of Indian agriculture. It is also a great earner of foreign exchange.

Question 9.
What are the main features of Agricultural development in India?
Answer:

  • India is a vast country. More than 70% of its population is dependent upon agriculture for livelihood.
  • The major foodgrains produced in India are rice and wheat.
  • Most of farms are not more than one hectare of land.
  • India is self-sufficient in the production of foodgrains .
  • In India, half of the total cultivable land is irrigated.

Question 10.
What has been the impact of mechanisation on agriculture?
Answer:
The earlier farmers used simple tools. Gradually on-driven ploughs were introduced. But, now in modern times the techniques have been changed. Now in developed countries all farm operations have been mechanised. It has reduced the number of people engaged in agricultural work. Many people can now work in industries and services.

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

Question 11.
What is Agriculture?
Answer:
The word Agriculture is derived from two Latin words ‘agri’ and ‘culture’. ‘Agri’ means’soil and ‘culture’ means cultivation or tilling. Agriculture hence refers to the cultivation of soil for growing crops and rearing of livestocks.

Question 12.
Name the factors influencing agriculture.
Answer:
The factors which influence agriculture are :

  1. Relief
  2. Soil conditions
  3. Temperature
  4. Rainfall.

Question 13.
What is plantation agriculture?
Answer:
It is special type of commercial farming which requires large amount of labour, technical efficiency, very large estates and capital. In this type of agriculture a simple crop of tea, rubber, coffee, sugarcane, cashew, banana or cotton is grown. The produce may be processed on the farm itself or in nearby factories. A well developed transport . network is also required.

Tropical regions of the world are major plantation areas. Rubber in Malayasia, coffee in Brazil, tea in India and Sri Lanka are some examples.

Question 14.
Name the different varieties or crops in India.
Answer:

  1. Cereals
  2. pulses and oilseeds
  3. Fibre crops
  4. Beverage crops
  5. Cash crops

Question 15.
Discuss the different types of fibres.
Answer:
Vegetable fibers are obatained from seeds, barks, leaves and fruit cases.
Animals fibres are produced from insects; such as silkworm and animals such as camels, sheep, goats, yaks, Hamas, rabbits, guanacos, alpacas, vicunas and reindeers.

Mineral fibres such as glass is made from silica sand.
Synthetic fibres are derived from chemical treatment of natural cellulose, which is i made from wood pulp.

Question 16.
What do you know about commercial agriculture?
Answer:
In this type of agriculture the main aim is to produce the crop for sale in the market. It can be intensive or extensive agriculture. The farmers try to keep the cost of production low. The framework is done by machines. This type of agriculture is practised in the prairies of North America, Pampas of South America, Steppes of Russia, Western Europe and in some parts of India.

Question 17.
Write the features of Intensive Subsistence Agriculture.
Answer:
It is a type of subsistence agriculture and its features are :

  • Intensive subsistence agriculture is done on small plot with simple tools.
  • Done by farmer and his family as labour.
  • Produce is used mainly by farmer so food grains are grown.
  • Rice is the main crop. Other crops are wheat, maize, pulses etc are cultivated.
  • Done mainly in thickly populated areas of south, southeast and east Asia.

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

Question 18.
Describe the main characteristics of shifting agriculture.
Answer:

  • In shifting agriculture, a plot of land is cleared by felling trees and burning them.
  • The ashes are then mixed with soil which works as a fertilizer.
  • After the soil loses its fertility, the land is abandoned. Cultivators move to a new plot.
  • It is practised in areas of heavy rainfall and quick generation of vegetation.
  • It is mainly done in Amazon basin, Tropical Africa, Southeast Asia and northeast India.
  • Crops like maize, yam, potatoes, and cassava are grown. This is also known as the ‘slash and burn’ agriculture.

Question 19.
Distinguish between :
(i) Subsistence farming and Commercial farming
Answer:

Subsistence Farming Commercial Farming
1. The practice of farming in which the crops are grown for home consumption by the farmer. 1. The practice of farming in which crops are grown for sale in the market or trade.
2. It is practised on small farms with simple tools and old technology. 2. It is practised on large farms with modern technology.
3. For example The production of wheat in some parts of country. 3. For example The production of sugarcane in U.P.

(ii) Intensive farming and Extensive farming.
Answer:

Intensive Farming Extensive Farming
1. Production is increased by using higher inputs and better agricultural techniques. 1.            Production is increased by bringing more and more land under cultivation.
2. This is practised in areas which are thickly populated. 2. This is practised in areas which are thinly populated.
3. This is practised in areas where there is less land available. 3.            This is done in areas where abundant land is easily available.
4. Livestock farming is little developed due to poor pastures. 4.            Livestock farming Supplements agriculture due to availability of grasslands.
5. Farms are small in size. 5. Farms are very large in size.

Fill in the blanks :

Question 1.
Shifting agriculture is also known as _________
Answer:
Slash and burn

Question 2.
_________, soil and climate are vital factors for agricultural activities.
Answer:
Topography

Question 3.
Advertising is an example of _________ activities.
Answer:
Tertiary

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

Question 4.
Jute is grown intensively in _________ and _________
Answer:
India, Bangladesh

Question 5.
Coarse grains are also called _________
Answer:
Millets.

Long Answer Type Questions

Question 1.
What is the importance of cotton? Explain the conditions of growth and areas of production of cotton and jute in India.
Answer:
Cotton. Cotton has been called ‘the universal fibre’. It is one of the most important fibres of all the fibres. It forms the basis of cotton textile industry. Cotton is the leading fibre crop of India. It is known from the writings of Herodotus that cotton has been in use in India since 3000 B.C.

Geographical Conditions of Growth

  • Temperature. Cotton needs uniformly high summer temperature between 22°C to 32°C. It requires a warm climate with bright sunshine. Frost is harmful to cotton plants.
  • Rainfall. Cotton needs light to moderate rainfall between 50 to 100 cm.
  • Irrigation. In arid treas, irrigation is used. It increases the yield per hectare as in Punjab.
  • Soils. Cotton grows best on rich, well-drained loamy soils or lava soils.

Types of Cotton:

  • The long-staple cotton. This cotton has a length of 25 mm and above.
  • The medium staple cotton. This cotton has a staple length between 18 mm to 25 mm.
  • The short-staple cotton. This cotton has a fibre length of less than 18 mm.

Area of Cultivation
Southern India produces more cotton than Northern India. Gujarat is the leading
producer of cotton in India with a production of 25% of the total production in the country.
1. Black cotton soil region. This is the chief cotton-growing area of India on the ‘lava soil’ of N.W. Deccan Plateau. Gujarat, Maharashtra, and Madhya Pradesh are the major cotton-producing states.

2. Red soil region. Medium staple cotton is grown in the red soil areas including the states of Tamil Nadu, Karnataka, and Andhra Pradesh. The yield is low.

3. Alluvial soil region. Long-staple cotton is grown on the alluvial soils of Northern Plains. The states of Punjab, Haryana, and Rajasthan are the important producers. Punjab has the highest yield per hectare due to its warm climate, fertile soils, and facilities of irrigation.

World Production. The U.S.A. is the leading producer of cotton in the world. China ranks second. India ranks third. Other main producers are Russia, Mexico, Egypt, Sweden, and Pakistan. Egypt is known for long-staple cotton. In the U.S.A., cotton production is decreasing.

PSEB 8th Class Social Science Solutions Chapter 4 Our Agriculture

Question 2.
Describe the different types of Farming.
Answer:
1. Shifting Agriculture. This farming method is practised by primitive people living in dense forests. The land is prepared by felling trees and burning the trees. People move from one area to another when the soil loses its fertility.

2. Subsistence Farming. In this method, farmers use primitive tools to cultivate their lands. Farmers in these regions produce agricultural goods, which are just sufficient to satisfy their own needs.

3. Commercial Farming. When farmers use modern tools and equipment such as tractors, threshers, winnowers, etc., and produce crops mainly to sell them in the market, it is called commercial farming.

4. Extensive Farming. This method is practised in countries where the population is sparse and the availability of land is more. Farmers use machines to a great extent, as the size of land holdings is large.

5. Intensive Farming. In this method of farming, the same piece of land is used throughout the year continuously. The soil is also very fertile. Farmers use more labourers, seeds that can yield more, better manures, and ensure a regular water supply.

6. Irrigation Farming. It is the type of farming, which mainly depends on irrigation through canals, wells, and tanks. Farmers cultivate their lands throughout the year.

Some of the important river valleys of the world where this method is followed are, the Ganga valley and the Indus valley in India, the Nile valley in Egypt, the Xi Jiang valley in China, Missouri, and San Joaquin valley in the United States of America.

7. Rainfed Farming. In the regions where the rainfall is not only seasonal but also scanty, farmers use different measures to cultivate their lands and use the scarce amount of rainwater efficiently. This is known as rainfed farming.

8. Mono-crop Farming. When the farmers specialize in the production of a single crop or if the soil and other natural factors allow farmers to cultivate only one crop that farming is known as one-crop or mono-crop farming.

9. Double and Multi-crop Farming. When two or more crops are cultivated in a plot of land, it is known as double or multi-crop farming. In this method, farmers apply scientific methods—use seeds that can give high yield, and apply manures in an appropriate manner.

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

by

Punjab State Board PSEB 8th Class Social Science Book Solutions Geography Chapter 3 Minerals and Energy Resources Textbook Exercise Questions and Answers.

PSEB Solutions for Class 8 Social Science Geography Chapter 3 Minerals and Energy Resources

SST Guide for Class 8 PSEB Minerals and Energy Resources Textbook Questions and Answers

I. Answer the following questions in 1-15 words :

Question 1.
Write the definition of mineral resources.
Answer:
Minerals are natural substances that are made up of one or more elements. These are found in the interior of the earth. These have a definite chemical composition. These are identified by their physical and chemical qualities.

Question 2.
Where do iron-ore is found in India?
Answer:

  1. Bihar: Singhbhum.
  2. Orissa: Mayurbhanjh.
  3. Chhattisgarh: Durg and Bastar.
  4. Karnataka: Bellary, Dharwar, Kudremukh.

Question 3.
What are the uses of copper?
Answer:
Copper is used for making utensils, coins, electrical wires and electronics. Their sheets are also made.

Question 4.
Name the famous gold mines in India.
Answer:
In Karnataka, Kolar and Hutti.
In Andhra Pradesh: Ramgiri.

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

Question 5.
How should we use atomic minerals?
Answer:
Atomic minerals should be used carefully. These should be used for the development of the country and not for destruction and pollution.

Question 6.
What are the non-conventional sources of energy?
Answer:
Water power, solar energy, wind power, geothermal energy and tidal energy.

Question 7.
Name the four types of coal.
Answer:

  1. Anthracite
  2. Bituminous
  3. Lignite
  4. Peat.

Question 8.
What are multipurpose projects?
Answer:
The dams built mainly for power generation are called multi- purpose projects as these provide many benefits at the same time.

II. Answer the following questions in 50-60 words :

Question 1.
Which are the countries from where iron ore is mainly found? Write down the different types of iron ore :
Answer:
Countries: Russia and its neighbouring countries, Australia, Brazil, U.S.A. produce large quantities of iron ore. India produces 5% iron ore in the world.

Types of Iron ore :

  1. Magnetite
  2. Haematite
  3. Limonite
  4. Siderite.

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

Question 2.
Write down a note on the importance of Bauxite.
Answer:
Aluminium is extracted from Bauxite. It makes up about 8 per cent of the earth’s crust. It is light, strong and a very good conductor of electricity. It is largely used in various industries like transportation (aircraft, ship building, automobiles), chemical industries, electrical goods, machines, etc. It is used in making utensils, coins, furniture, sheets, packing material, photo-frames, pipes, etc. It is the basis of our telecommunication systems as it is used in radios, telegraphs, televisions and electrical wires. Due to its wide uses, it has been described as the ‘champion of metals’ or ‘the metal of the twentieth century’.

Question 3.
What is the importance of natural gas in our life and name the major areas in our country where it is found?
Answer:
Natural gas is produced in areas producing petroleum. When an oil well is dug, Natural gas is found in upper layers.

Use: It is used in homes for cooking, in vehicles and in industry.

Production: All the petroleum-producing countries produce Natural gas. The U.S.A. is the leading producer in the world. Russia, Middle East, Canada, Uzbekistan are other producers. Natural gas is produced in some parts of India. These include the Krishna-Godavari basin, Bay of Bengal-Orissa region and Barmer region of Rajasthan. Gulf of Cambay and Kutch region in Gujarat is a potential area. About 75% of the production of India comes from Bombay High.

Question 4.
Name the important factors which are favourable for the generation of Hydroelectricity?
Answer:
The development of water power (Hydro-electric power) depends upon the following factors:

  1. Uneven relief. Mountainous areas provide quite good sites for the development of water power. Such areas provide rapids or falls.
  2. Abundant rainfall. Fairly = heavy rainfall uniformly distributed throughout the year is necessary for water power development.
  3. Presence of huge rivers and waterfalls. There should be some large rivers like Indus or Nile to provide large and regular supply of water.
  4. Presence of lakes. The presence of lakes along the course of a river helps to regulate water flow naturally.
  5. Nearness to market. The consuming areas should be near the power stations to avoid the loss during transmission.

III. Answer the following questions in about 125-130 words :

Question 1.
What are energy resources? What is their contribution towards the development of the country? Write in detail about any two energy resources.
Answer:
Coal: Coal is the prime source of energy. It is often called the ‘Mother of Industries’. It has been the basis of industrial revolution. Coal is used as a raw material in iron and steel, chemical industries. India ranks seventh in the world as regards coal reserves. The total proven coal reserves are nearly 214,000 million tonnes. These reserves will not last long. The major states known for coal reserves are Jharkhand, Bihar, Orissa, West Bengal, Chhattisgarh, M.P., Andhra Pradesh and Maharashtra. Coal production is 330 million tonnes (4% of world).

Distribution: India has two types of coalfields :
(a) Gondwana coalfields (98%)
(b) Tertiary coalfields (2%).

(a) Gondwana coalfields: These belong to the period of Gondwana age. Nearly 3/ 4th of coal deposits are found in Damodar valley (Damuda series). Godavari, Mahanadi, Son and Wardha valley have also coal deposits.
PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources 1

  1. W. Bengal. West Bengal has the oldest coalfield of India at Raniganj. It covers an area of 1267 sq. km.
  2. Jharkhand and Bihar. These two states produce 50% coal of India. The major coalfields of Jharia, Bokaro, Karanpura, Daltonganj are found in Damodar valley. Coking coal from this coalfield is supplied to steel centres of Jamshedpur, Asansol, Durgapur and Bokaro.
  3. Chhattisgarh and Madhya Pradesh have Son valley coalfields of Suhagpur, Korba, Rampur, Tatapani, Singrauli.
  4. Petroleum: In about 10 lakh sq. km oil-bearing rocks are found in India. The oil reserves in India are estimated to be about 4000 million tonnes.

The first oilfield in India was discovered in 1867 at Makum in Assam. At present the production is as below (334 lakh tonnes) :

  1. Assam: In Assam oil is produced in Digboi, Moran, Naharkatiya and Sibsagar regions.
  2. Gujarat: In Gujarat oil is produced in the Gulf of Cambay region at Kalol, Ankleshwar, Lunej, etc.
  3. Maharashtra: Oil has struck in the off-shore region at Bombay High along the coast of Mumbai. It is the leading producer of crude oil in India. North Basin and South basin are the important oilfields.

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources 2
The production of oil in India is increasing everywhere under the organization of Oil and Natural Gas Commission.

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

IV. Map Skill

Question 1.
Show one important area of minerals and energy resources on map of India
1. Iron ore
2. Manganese
3. Gold
4. Mica
5. Coal
6. Petroleum.
Answer:
PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources 3

V. Activity

Question 1.
Prepare a list of atleast ten minerals.
Answer:

S.No. Name of the minerals Name of state of India in which mineral is found Use of the mineral
1. Iron ore Jharkhand Iron steel industries
2. Manganese Madhya Pradesh Steelmaking
3. Gold Karnataka Jewellery
4. Copper Jharkhand Electrical industries
5. Mica Bihar Chemical Industries
6. Uranium Jharkhand Utensils
7. Bauxite Andhra Pradesh Chemical
8. Coal Jharkhand Power
9. Petroleum Assam Power
10. Hydroelectricity Maharashtra Power

PSEB 8th Class Social Science Guide Minerals and Energy Resources Important Questions and Answers

Multiple Choice Questions :

Question 1.
Which one of the following is not a type of mining?
(a) Open cast
(b) Shaft
(c) Drilling
(d) Shaft.
Answer:
(d) Shaft.

Question 2.
Which is the hardest mineral?
(a) Diamond
(b) Granite
(c) Basalt
(d) Gatbro.
Answer:
(a) Diamond.

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

Question 3.
Which is the first metal discovered by man?
(a) Copper
(b) Silver
(c) Gold
(d) Iron.
Answer:
(a) Copper.

Question 4.
Name the diamond which is rarest diamond.
(a) Green diamond
(b) White diamond
(c) Pink diamond
(d) Brown diamond.
Answer:
(a) Green diamond.

Question 5.
Which is a ferrous mineral?
(a) Bauxite
(b) Iron
(c) Mica
(d) Coal.
Answer:
(b) Iron.

Question 6.
What is the name of mining shown in the picture?
PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources 4
(a) Open Cast
(b) Shaft
(c) Drilling
(d) Shaft mining.
Answer:
(d) Shaft mining.

Question 7.
Which source of energy is the activity in the picture associated with?
Or
Seeing the picture tell the source to which it belongs.
PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources 5
(а) Hydroelectricity
(b) Solar energy
(c) Wind energy
(d) Nuclear (Atomic) energy.
Answer:
(a) Hydroelectricity.

Fill in the Blanks :

Question 1.
The __________ metals do not contain metals.
Answer:
Non-Metallic

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

Question 2.
Gondwana coalfields belong to the period of __________ age.
Answer:
Gondwana

Question 3.
Biogas is produced in __________ areas.
Answer:
Rural

Question 4.
Khetri is famous for __________
Answer:
Copper

Question 5.
In Gujarat oil is produced in the __________ region.
Answer:
Gulf of camboy.

True/False :

Question 1.
Energy generated by Tides is called Tidal energy.
Answer:
True

Question 2.
West Bengal has the oldest coalfield of India.
Answer:
True

Question 3.
Iron is a non-ferrous mineral.
Answer:
False

Question 4.
Jharia is famous for Atomic energy.
Answer:
False

Question 5.
Gold metal is used for decoration.
Answer:
True.

Very Short Answer Type Questions

Question 1.
Into how many categories can minerals be classified? Give two examples of each.
Answer:
Minerals are grouped into three categories :

  1. Metallic Minerals. Iron ore, tin.
  2. Non-metallic Minerals. Diamond, Gypsum.
  3. Atomic Minerals. Uranium, Thorium.

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

Question 2.
Distinguish between Ferrous and Non-ferrous minerals.
Answer:

Ferrous minerals Non-ferrous minerals
1. The metallic minerals which contain iron content are called ferrous minerals (Fe). 1. The minerals which do not contain iron (ferrous) content are called non-ferrous minerals (Nfe).
2. Iron, Manganese, Chromite, Cobalt, etc. are ferrous minerals. 2. Copper, Lead, Zinc, Aluminium are non-ferrous minerals.

Question 3.

What are the uses of Manganese?
Answer:

  1. It is used for manufacturing bleaching powder.
  2. It is used in insecticides.
  3. It is used for making paints and batteries.

Question 4.
Where does India rank in the production of manganese in the world? Where is it found in India?
Answer:
India ranks second in world production of Manganese. In India the main producing areas are Karnataka, Orissa, Madhya Pradesh, Maharashtra, West Bengal and Goa.

Question 5.
What is Bronze? What is its use?
Answer:
It is a hard and strong product. Tin and copper are mixed to make it. It is used in making tools and weapons.

Question 6.
Where is copper found in the world ? Name the copper producing areas in India.
Answer:
USA, Russia, Chile, Zambia, Canada and Zaire are the main producers of copper. In India copper is found in Singhbhum (Jharkhand), Balaghat (Madhya Pradesh) and Jhunjhunu, Alwar (Rajasthan).

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

Question 7.
Which two states of India are large producer of Bauxite? Name two copper producing areas of these states.
Answer:
Jharkhand and Rajasthan are Bauxite producing states of India. Copper is mined at Singhbhum and Khetri.

Question 8.
What are the uses of Gold?
Answer:
Gold is a valuable metal :

  1. It is used for making ornaments and articles for decoration.
  2. It is used for gold plating, teeth covers and medicines.

Question 9.
What are the uses of copper?
Answer:
Copper is a soft and brown-coloured metal. It has been used by man for a very long time. It is mixed up with tin to be known as Bronze. It is used in the production of utensils, coins, electric wires.

Question 10.
Which minerals are used to produce atomic energy?
Answer:
Uranium, Thorium, Lithium and Zircon are used to produce atomic energy.

Question 11.
Why is petroleum called Rock oil?
Answer:
Petroleum or ‘mineral oil is called rock oil because it is formed in sedimentary rocks. It is called crude oil.

Question 12.
Which country is the largest producer of Gold in the world? And how much?
Answer:
South Africa is the largest producer of gold in the world. It produces about 70% gold of the world.

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

Question 13.
What is Mica? Why is it used in electrical goods industry?
Answer:
Mica is black or brown or white transparent material. It is a non-metallic .mineral. It is non-conductor of electricity. So it is used in electrical goods industry.

Question 14.
Describe the different methods of extracting minerals.
Answer:
Taking out minerals from rocks is called mining :

  • Open cast mining: Minerals at shallow depths are taken out by removing the surface layer.
  • Shaft Mining: Minerals at depth are taken out by making deep bores.
  • Drilling: Deep wells are bored to take out petroleum.
  • Quarrying: Minerals at surface are dug out.

Question 15.
Most industries are concentrated around coal mines.
Answer:
Most industries are concentrated around coal mines because coal is an important source of energy. It is key mineral and fuel for the industries. It is used as a power resource in many industries. Many industries use it as a raw material. So most industries are concentrated around coal mines.

Question 16.
Petroleum is referred to as “black gold”. Why?
Answer:
Nowadays petroleum is a major source of energy in the world. Many byproducts such as kerosene, fuel, lubricating oils etc. are obtained from it. Petrochemical products have become very useful. Petroleum is used in agro-industry, paints, perfumes, transport, etc. So it is rightly called the “black gold”.

Question 17.
Distinguish between conventional and non-conventional sources of energy.
Answer:

Conventional Sources Non-conventional Sources
1. The sources of energy which have been used since a long time are called the conventional sources of energy. . 1. The sources of energy which have not been commonly used are called non conventional sources of energy
2. Wood, fuel, coal, petroleum gas and water power are conventional sources of energy. 2. Wind, tidal power, Geothermal energy, bio gas, solar energy are non conventional sources of energy.

Question 18.
Distinguish between
(i) Thermal power and Hydel power.
Answer:
Thermal Power and Hydel Power

Thermal Power Hydel Power
1. It is expensive. 1. It is comparatively cheaper.
2. It is a limited resource. 2. It is an unlimited resource.
3. It creates problems of atmospheric pollution. 3. It is non polluted.
4. The electricity generated by coal or petroleum is called thermal power. 4. The electricity generated by running water is called hydel power.

(ii) Anthracite coal and Bituminous coal.
Answer:
Anthracite coal and Bituminous coal

Anthracite coal Bituminous coal
1. It is the best quality of coal. 1. It is the low quality of coal.
2. It causes very less pollution. 2. It causes more pollution.
3. It gives more energy. 3. It gives less energy.
4. It is found only in J & K. 4. It is found in West Bengal, Orissa, Chhattisgarh and Jharkhand.

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

Question 19.
How should the natural resources be conserved?
Answer:
The natural resources should be used carefully in a planned manner. No resource should be wasted. These should be used so that the future generations can also use these.

Question 20.
Distinguish between Metallic and Non-metallic minerals.
Answer:

Metallic Minerals Non-Metallic Minerals
1. Metals are malleable i.e., they can be beaten into sheets. 1. They are brittle in nature and cannot be beaten into sheets.
2. They are good conductors of heat and electricity. 2. They are bad conductors of heat and electricity.
3. All metals are solids. 3. They may be solids, liquids and gases.
4. For Example iron, copper. 4. For Example sand, diamonds.

Question 21.
‘Human civilisations are associated with discovery of minerals.’ Give example.
Answer:
Mining is an age-old activity. The use of minerals is marked with different stages of human civilisation. During 5000 B.C., copper age existed. During 3000 B.C., Bronze age and during 1400 B.C., iron age were developed.

Question 22.
What are the alternative sources of energy?
Answer:
There are other sources of energy as well. They include hydropower, geothermal, nuclear, solar and wind. These are also referred to as the alternative energy sources.

Question 23.
Many African countries have large potential of water resources but they have not used it to generate hydro-electricity.
Answer:
Large amount of capital is required for making dams on rivers, fixing machines and turbines and buying of transmission lines. So in spite of the water resources they are not used to generate hydro-electricity.

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

Question 24.
Name four main belts where iron ore is found.
Answer:
The four main iron ore belts are :

  1. Orissa – Jharkhand belt
  2. Durg – Bastar Chandarpur belt
  3. Bellary – Chick Manglur belt
  4. Maharashtra – Goa belt.

Question 25.
‘Mineral conservation can delay a crisis.’ Explain.
Answer:
Due to growing population, the use of minerals is increasing at an alarming rate. Minerals will not last long. We need to find substitutes, reduce consumption, recycle mineral resources. It can delay a mineral crisis.

Question 26.
Classify the following metals :
(i) Ferrous
Answer:
Ferrous: Iron and Manganese

(ii) Non-ferrous
Answer:
Non-ferrous: Copper and Lead

(iii) Light metal
Answer:
Light metal: Aluminium

(iv) Rare metals.
Answer:
Rare metals: Zirconium.

Question 27.
List three basic ways through which energy is-obtained.
Answer:
Energy is the capacity to do work. It can be obtained by :

  • Direct heating like fire, sun, etc.
  • Electricity
  • Stored energy in the form of a battery.

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

Question 28.
Describe the different types of coal.
Answer:

  1. Peat: Peat is the first stage of coal development. It is dark brown in colour. It has about 35 per cent carbon content.
  2. Lignite: Lignite is the next stage of coal formation, which has almost 50 per cent carbon.
  3. Anthracite: Lignite becomes sub-bituminous, bituminous and eventually anthracite coal. Anthracite has more than 85 per cent carbon. It is the best quality of coal. It is very hard, compact, black in colour. It ignites slowly and bums with short blue flame.

Question 29.
Describe the formation of coal.
Answer:
Coal is a black or brown rock consisting mainly of carbon. Coal is formed by the decomposition of vegetation of last ages. Most of coal deposits were formed in carboniferous age about 300 million years ago.

Question 30.
Describe natural gas as a source of conventional energy.
Answer:

  1. Natural gas is found with petroleum deposits.
  2. It is released when crude oil is brought to the surface.
  3. It is used as a domestic and industrial fuel.
  4. Russia, Norway, UK and the Netherlands are the major producers of natural gas in the world.
  5. Jaisalmer, Krishna-Godavari delta. Tripura and some areas off shore in Mumbai have natural gas resources in India.
  6. Very few countries in the world have sufficient natural gas reserves of their own.

Question 31.
Describe solar energy.
Answer:
Solar Energy:

  1. Sun provides heat and light energy every day.
  2. Solar energy trapped from the sun is used in solar cells to produce electricity.
  3. These cells are joined into solar pan&b to generate power for heating and lighting purpose.
  4. The technology of utilising solar energy benefits tropical countries with abundant sunshine.
  5. Solar energy is also used in solar heaters, solar cookers, solar dryers along with community lighting and traffic signals.

Question 32.
Explain wind energy.
Answer:

  1. Wind is an inexhaustible source of energy.
  2. Windmills have been used for grinding grain and lifting water since times immemorial.
  3. At present high speed wind rotate the windmill which is connected to a generator to produce electricity.
  4. Wind farms are clusters of wind mill. They are located in coastal regins and in mountains passes where strong and steady win blows.
  5. Wind farms are found in Netherland, Germany, Denmark, UK, USA and Spain, ‘ They are known for wind energy production.

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

Question 33.
Give an account of nuclear power.
Answer:
Nuclear power:

  1. Nuclear power is obtained frm energy stored in the nuclei of atoms of naturally occurring radioactive fuels like uranium and thorium.
  2. These fuels undergo nuclear fission in nuclear reactors and emit power.
  3. USA and Europe are the greatest producers of nuclear power.
  4. In India: Rajasthan and Jharkhand have large deposits of uranium.
  5. Thorium is found in large quantities in the monozite sands of Kerala.
  6. Nuclear power stations in India are located in Kalpakkam (Tamil Nadu), Tarapur (Maharashtra), Ranapratap Sagar near Kota (Rajasthan), Narora (Uttar Pradesh) and Kaiga (Karnataka).

Question 34.
How is geothermal energy used?
Answer:
Geothermal Energy

  • Heat energy obtained from the earth is known as geothermal energy.
  • The temperature in the interior of the earth increases with increase in depth.
  • This heat energy comes on the surface in the form of hot springs. This heat energy is used to generate power.

Question 35.
Rajan lives in West Bengal. Which cereal crop should he sow in his field to maximise his profit?
Answer:
Rice.

Short Answer Type Questions

Question 1.
Describe the production of mica in world and in India.
Answer:
U.S.A., Russia, India, France, Argentina and South Korea are the main producers of Mica. India is the leading producer of mica in the world. But the production of mica is decreasing in India.

It is due to two factors :

  1. The demand for mica is decreasing in the world.
  2. The use of substitutes is increasing.

90% of the production of Mica in India comes from three states of Andhra Pradesh, Rajasthan and Jharkhand. Other producers are Bihar, Gujarat, Kerala, Madhya Pradesh, Chhattisgarh, Himachal Pradesh. The main districts are Nellore, Vishakhapatnam, Krishna (Andhra Pradesh), Jaipur, Udaipur, Bhilwara (Rajasthan), Gaya (Bihar), Hazaribagh (Jharkhand).

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

Question 2.
What is Nuclear Energy? Name the areas in India producing nuclear minerals.
Answer:
The energy generated by nuclear minerals is called nuclear energy. Uranium, Thorium, Lithium are nuclear minerals.

Areas of Production :

  • Uranium. Singhbhum, Hazaribagh (Jharkhand), Gaya (Bihar) Saharanpur (U.P.) and Udaipur (Rajasthan).
  • Thorium. Kerala, Jharkhand, Bihar, Rajasthan and Tamil Nadu.
  • Lithium. Jharkhand, Madhya Pradesh, Rajasthan, Chhattisgarh, Kerala.

Question 3.
Describe the importance of Natural Resources in our day to day life. Name the main areas of Natural Resources.
Answer:
Natural resources are free gifts of nature. These are very important for our lives. These are the index of a country’s progress and strength. These are called ‘the backbone of a country.

Areas of Natural Resources:

  • India’s 30% of the total area is covered with mountains. These have huge water and forest resources.
  • About 27% of the total area is covered with plateaus. These are storehouses of minerals.
  • About 43% of the total area is covered with plains. These have fertile soils and agriculture is well developed. These are ‘granaries’ of India.

Question 4.
Describe the Non-conventional sources of energy produced in India.
Answer:
Non-conventional sources of energy. Today non-conventional sources of energy include wind, tides, geothermal heat, biogas, farm and animal waste including human excreta.

All these sources are renewable or inexhaustible.
1. Wind energy: It can be used for generating electricity. It is estimated that wind alone can provide 2000 MW of electricity. The states of Gujarat, Tamil Nadu, Maharashtra and Orissa are better placed in regard to this energy. Areas with constant and high speed winds are suitable for the purpose.

2. Tidal energy: The Gulfs of Kutch and Cambay are ideally suited to develop electricity from the energy produced by high tides entering to narrow creeks.

3. Geo-thermal energy: India is not rich in this source. However, efforts are on to utilize natural energy of the hot springs at Manikaran in Himachal Pradesh.

4. Energy from urban waste: A pilot for demonstration purposes had already been set up in Delhi to treat solid municipal waste for conversion into energy. It produces nearly 4 MW energy every year. Sewage in cities is used for generating gas and electricity.

5. Biogas based power plants: Bagasse, farm wastes, rice husk are being used to produce electricity.

6. Farm animal and human wastes (Urja Gram): By using biomass, animal poultry waste and human excreta, gobar gas plants are being set up in villages.

7. Solar energy: Solar voltaic cells are used to generate solar energy.

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

Question 5.
Environmental aspects must be carefully looked into before building huge dams.
Answer:

  • Dams create an imbalance in the earth’s equilibrium.
  • Deforestation leads to environmental pollution.
  • People are displaced.
  • Cities/villages/towns are shifted causing untold hardships to people.
  • Silting of lakes a problem.

Fill in the blanks :

Question 1.
Russia is rich in __________ resource.
Answer:
Natural gas

Question 2.
Processing of digging out of minerals is known as __________
Answer:
quarrying

Question 3.
Biogas is produced in __________ areas.
Answer:
rural

Question 4.
India __________ in ferrous minerals.
Answer:
is rich

Question 5.
Australia is the largest producer of __________ in the world.
Answer:
bauxite

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

Question 6.
China and India have large __________ are deposits.
Answer:
iron.

Long Answer Type Questions

Question 1.
What is Hydel power? How is it generated? Describe its production in India and world.
Answer:
Hydel power is generated through falling water. Dams are built on rivers, the water is dropped from a height to rotate turbines. Due to friction, turbines generate electricity.

Production: Many countries have sufficient water resources. These countries produce large quantities of Hydel power. U.S.A., Russia, Japan, Germany, Canada, England, France, Italy, Poland, Brazil and India are the main producers. U.S.A. produces 31% water power of the world.

Hydel power in India. India produces sufficient Hydel power. But India’s share is only 1% in world production. Rivers and canals are the main sources.

  1. Himalayan rivers
  2. Peninsular rivers.

Ganga, Brahmaputra and tributaries are snow fed and perennial rivers. So these have large capacity to generate water power with 18% of total potential of India. But peninsular rivers are seasonal and depend upon rainfall. So their capacity is low.

Distribution: All the states, except, Goa produce Hydel power. Andhra Pradesh, Karnataka, Maharashtra, Punjab, Tamil Nadu, Orissa, Kerala states have large capacity. Uttarakhand and Himachal Pradesh are rich in Hydel power resources. We have to develop these resources.

Important: Projects,

  • Nagarjun Sagar Dam-Karnataka.
  • Ganga Hydro-electric system-U.P.
  • Tata Hydro-electric Grid-Maharashtra.
  • Hirakud Dam-Orissa.
  • Pandoh Project-Himachal Pradesh.
  • Bhakra-Nangal Project-Punjab.

PSEB 8th Class Social Science Solutions Chapter 3 Minerals and Energy Resources

Question 2.
Describe the economic importance of minerals. Explain the main types of minerals.
Answer:
Minerals. Mineral resources are of great use to man. Minerals have been called ‘The Gifts of Nature’. Mineral resources have been used since pre-historic times. Human civilisation has seen many ages like the stone age, copper age and iron age. Modern industrial and economic development depends upon the production and utilization of minerals.

Types of Minerals: There are 70 to 80 minerals found on the surface of the earth. These can be divided into three types :

  1. Non-Metallic Minerals. These include salt, mica, limestone, graphite, potash, gypsum.
  2. Metallic Minerals. These include iron, copper, aluminium, gold, silver. These can be melted into useful metals.
  3. Fuel Minerals. These include coal, oil and natural gas. These are called sources of power.

Importance of Minerals :

  • Industries. Minerals form the basis of heavy industries like iron and steel. Minerals are called ‘vitamins’ of industry.
  • Machinery. Minerals provide machinery for modern manufacturing.
  • Transport. Minerals are used in the making of different means of transportation.
  • Sources of Energy. Minerals provide energy to modern industries.

Question 3.
Describe the production of Petroleum in India.
Answer:
Production. In about 10 lakh sq. km. oil-bearing rocks are found in India. The oil reserves in India are estimated to be 50 crore metric tons.
The first oilfield in India was discovered in 1867 at Makum in Assam. At present the production is as under:

  1. Assam: In Assam, oil is produced in Digboi, Moran, Naharkatiya, and Sibsagar regions.
  2. Gujarat: In Gujarat, oil is produced in the Gulf of Cambay region at Kalol, Ankleshwar, Lunej, etc.
  3. Maharashtra: Oil has struck in the offshore region at Mumbai High along the coast of Mumbai. It is the leading producer of crude oil in India. North Basin and South Basin and Albet islands are the important oil fields.
  4. The production of oil in India is increasing everywhere under the organization of the Oil and Natural Gas Commission. The production of oil in India was estimated to be about 210 lakh tonnes in 2001.