PSEB 7th Class Social Science Solutions Chapter 13 Towns, Traders and Craftsmen

Punjab State Board PSEB 7th Class Social Science Book Solutions History Chapter 13 Towns, Traders and Craftsmen Textbook Exercise Questions and Answers.

PSEB Solutions for Class 7 Social Science History Chapter 13 Towns, Traders and Craftsmen

SST Guide for Class 7 PSEB Towns, Traders and Craftsmen Textbook Questions and Answers

I. Answer these questions :

Question 1.
Name any four pilgrimage centres.
Answer:
Nankana Sahib, Amritsar, Kurukshetra, Haridwar, Badrinath, Mathura, Banaras, Jagannath Puri, Dwarka Puri etc. are few of the pilgrimage centres.

Question 2.
Which Guru laid the foundation of Amritsar gnd when?
Answer:
Amritsar is a famous religious place of the Sikhs. It was founded by 4th Guru Sri Guru Ramdas Ji in 1577 A.D. In the beginning, the name of Amritsar was Chak Guru Ramdas. During the time of Sri Guru Ram Das Ji, the work of digging was started on two ponds named Amritsar and Santokhsar, but after Guru Ramdas Ji, fifth Guru Arjan Dev Ji completed this work.

Importance: In 1604 A.D., the placement of Sri Guru Granth Sahibji was done in Sri Harmandar Sahib. In 1609 A.D., Sixth Guru Sri Guru Hargobindji built Shri Akal Takht Sahib in front of Sri Harmandar Sahib. Here, Guruji accepted the gifts of horses and weapons from Gursikhs. Here, discussions were also held on political affairs. Even today, the religious decisions of Sikhs are announced from here. In 1805 A.D., Maharaja Ranjit Singh gave golden covering on the domes of Sri Harmandir Sahib. Since then it has been called ‘The Golden Temple’.

Question 3.
Where the Surat is situated?
Answer:
Surat is a famous port and trading city. It io located in the state of Gujarat. It is a big industrial and trading city. Shivaji plundered it twice and got hold of big riches. During 12th century the Parsis occupied Surat. In 1512 A.D., the Portugese occupied it. In 1573 A.D., Surat came under the control of Akbar and became a major trading city.

In 1612 A.D., the English get many facilities from Emperor Jahangir for trading in Surat. The Portugese, the Dutch and the French also established their trading centres. In 1759 A.D., the English captured the Surat port but they could control it completely in 1842 A.D. The Khwaja-Sahib mosque and nine-Sayyed mosque located here are very famous. The Swami Narain temple and the old Jain temples located here are also very important.

II. Fill in the blanks:

Question 1.
Amritsar was founded by _________
Answer:
Sri Guru Ramdas Ji

Question 2.
Surat is a _________ city.
Answer:
famous port and trading

PSEB 7th Class Social Science Solutions Chapter 13 Towns, Traders and Craftsmen

Question 3.
Nankana Sahib is situated in _________
Answer:
Pakistan

Question 4.
India had many port _________
Answer:
cities.

III. Write True or False against the each statement:

Question 1.
Mohenjodaro was the capital city of Indus valley people.
Answer:
True

Question 2.
In 1629, Shah Jahan made a new capital in Delhi.
Answer:
False

Question 3.
Surat was an important pilgrimage centre.
Answer:
False

Question 4.
Fatehpur Sikri was the capital town of Mughals.
Answer:
True

PSEB 7th Class Social Science Solutions Chapter 13 Towns, Traders and Craftsmen

Question 5.
Lahore was a commercial town in Medieval period.
Answer:
True

IV. Activity:

Question 1.
Make a list of the following (four each).
(a) Capital towns
(b) Port towns
(c) Commercial towns
(d) Pilgrimage centres
Answer:
(a) Capital towns: Ajmer, Kanauj, Delhi, Agra.
(b) Port towns: Goa, Cochin, Surat, Broach?
(c) Commercial towns: Lahore, Multan, Surat, Ahmedabad.
(d) Pilgrimage centres: Nankana Sahib, Amritsar, Kurukshetra, Haridwar.

PSEB 7th Class Social Science Guide Towns, Traders and Craftsmen Important Questions and Answers

Multiple Choice Questions

Question 1.
Which of these is the type of town?
(a) Temple town
(b) Commercial town
(c) Administrative town
(d) All of these.
Answer:
(d) All of these.

Question 2.
Which of these was the capital of Chola dynasty?
(a) Thanjavur
(b) Masulipathnam
(c) Surat
(d) Hampi.
Answer:
(a) Thanjavur.

PSEB 7th Class Social Science Solutions Chapter 13 Towns, Traders and Craftsmen

Question 3.
Kings used to hold courts at _________ to give orders to subordinates.
(a) Temples
(b) Royal courts
(c) Mandapas
(d) Fort.
Answer:
(c) Mandapas.

Question 4.
Who built Rajarajeshvara temple?
(a) Raj Raja IV
(b) Raj Raja I
(c) Sultan of Bijapur
(d) None of these.
Answer:
(b) Raj Raja I.

Question 5.
The process by which cities develop is known as
(a) Civilization
(b) Urbanization
(c) Metropoltian
(d) Modernization.
Answer:
(b) Urbanization.

Question 6.
Pilgrimage centre which slowly developed into townships was
(a) Varindavan
(b) Ajmer
(c) Tiruvannamalai
(d) All of these.
Answer:
(d) All of these.

Question 7.
Who gave right to temples to collect taxes from traders?
(a) Kings
(b) Temple authority .
(c) Zamindars
(d) Both (a) or (c).
Answer:
(d) Both (a) or (c).

Short Answer Type Questions

Question 1.
Give a list of the following during the medieval period.
Answer:

  1. Capital Cities: Lahore, Fatehpur Sikri, Delhi, Agra.
  2. Port Cities: Cochin, Surat, Bharoch, Sopara.
  3. Trading Cities: Delhi, Agra, Surat, Ahmednagar.

PSEB 7th Class Social Science Solutions Chapter 13 Towns, Traders and Craftsmen

Question 2.
Give two means which give us information about the Mughal administration.
Answer:

  1. The travellogue of Bernier.
  2. The maps prepared by William Hawkins and Sir Thomas Roe.

Question 2 A.
Write names of any two capital towns of Mughal Empire.
Answer:
Two main capital cities of the Mughal Empire were Delhi and Agra.

Question 3.
How were cities developed?
Answer:
After the development of agriculture, men started living near farms. This gave birth to the concept of villages. When the number of people increased (population), some of these villages became cities. Some of these cities were developed because of the activities of religious personalities, traders, artisans or because of ruling class. These cities, came to be known as capital cities, religious cities, port cities and trading cities.

Question 4.
Give information about the capital cities during the ancient period and the Mughal period. .
Answer:
Ancient period:

  • Harappa and Mohenjodaro were the capital cities of Indus Valley Civilization.
  • During Vedic period, Ayodhya and Inderprasatha were the capital cities.
  • In 600 B.C., 16 states had their own capital cities. The main were Kausambi, Pataliputra and Vaishali.

Rajput Period:

  • Under Rajput rulers, Ajmer, Kanauj, Tripuri, Delhi, Agra, Fatehpur Sikri, etc. were developed as capital cities.
  • In South India, Kanchi, Badami, Kalyani, Vengi, Devagiri, Manyakhet, Tanjavur and Madurai, etc. were capital cities.

Sultanate and the Mughal periods:

  • During Sultanate period, Lahore and Delhi developed as capital cities.
  • During the dughal period Delhi, Agra, Fatehpur Sikri were the capital cities.

Question 5.
In India many port cities were developed. Why?
Answer:
India is sorrounded by the sea on three sides. So, in India many port cities were developed as trading centre.

PSEB 7th Class Social Science Solutions Chapter 13 Towns, Traders and Craftsmen

Question 6.
Name two important ports of eastern coast of India during Medieval period.
Answer:
Vishakhapatnam (Modem Andhra Pradesh) and Tamralipti.

Question 7.
Discuss the contribution of traders and artisans in the economic development of India.
Answer:
The Indian traders and artisans gave important contribution in the economic development of India. The Indian artisans were skilled in preparing best quality stock. They were very skilled in textile industry. The cloth prepared by them was world famous whether it was woolen, cotton, silky. The leather goods were also very popular.

In the medieval period, there was development of the art of making alloys. The blacksmiths and’ goldsmiths prepared best quality goods. The traders exported these goods to other countries. And thus, India was turned into a “Golden Sparrow”.

Question 8.
Write about the historical importance of Lahore City.
Answer:
Lahore is a famous city of Pakistan. During the medieval period, it was an important Indian city. During the times of Turk invasion, Lahore was the capital of Hindu ruling dynasty. After that, it remained the capital of Qutub-ud-din Aibak and Iltutmish. Iltutmish later on, made Delhi his capital.

During the times of invasion of Babar, Daulat Khan Lodhi was the Governor of Punjab. During the administration of Mughals, Lahore was«the capital of the state of Punjab. In 1761 A.D., Lahor-e was captured by the Sikhs. In 1799 A.D., Maharaja Ranjit Singh made Lahore his capital. In 1849 A.D. Lahore came under the control of the British. From 1849 to 1947 A.D. Lahore remained the capital of Punjab state. At the time of partition, Lahore! became a part of Pakistan.

Question 9.
Discuss the sources that tell us about towns in the Mughal period.
Answer:

  1. The travelogues of a Portuguese visitor named Duarte Barbosa and an English visitor named Ralph Fitch tell us about the cities of that period
  2. The map of the Mughal empire in 1629 A.D. shows places like Thatta, Lahore, Surat, and Multan. This map was prepared by Hondiu.
  3. The government documents related to the land revenue in the Mughal period give us information about old and new cities.

PSEB 7th Class Social Science Solutions Chapter 12 Monumental Architecture

Punjab State Board PSEB 7th Class Social Science Book Solutions History Chapter 12 The Creation of an Empire – The Mughal Empire Textbook Exercise Questions and Answers.

PSEB Solutions for Class 7 Social Science History Chapter 12 Monumental Architecture

SST Guide for Class 7 PSEB Monumental Architecture Textbook Questions and Answers

I. Answer the following questions :

Question 1.
Which are the main temples of Northern India?
Answer:
During the period of 800-1200 A.D., a number of temples were built in North India. The Vishnu temple at Jagannath Puri, Lingaraj temple at Bhubaneswar, the Sun temple at Konark, the Mahadeva at Khajuraho in Bundelkhand, Tejpal temple at Mount Abu, are the important temples of North India.

Question 2.
Describe the main features of Indian-Muslim architecture?
Answer:
The main features are as follows :

  • This style was the remix of Turk, Afghan and Indian style.
  • Many mosques and tombs were built in this style. Pillars, minarets, and domes are the main features of this style.
  • On the walls of these buildings, writings have been done taken from the holy ‘Quran’.
  • On the ‘Allai Darwaza’ which was built in the period of Alauddin Khalji, red stone and white marble has been used.
  • In many buildings pillars have been used.

Question 3.
Which are the temples of the Southern India?
Answer:

  • Raj Rajeshwar Temple built by Chola King Rajraja.
  • Gangaikondcholpuram temple built by the Chola king Rajendra I.
  • The Kailash Temple in Ellora built by Rashtrakuta rulers.
  • Brihadeshwara Temple in Tanjavur.

PSEB 7th Class Social Science Solutions Chapter 12 Monumental Architecture

Question 4.
Why Mughal Emperor Shah Jahan is calledi the ‘Prince of Builders’?
Answer:
Shah Jahan was very fond of building structures. All the buildings built by him have a special place from the viewpoint of art and beauty. In Agra he built Jahangir Mahal, Rani Jodhabai palace, Moti Masjid of Red Fort and Taj Mahal, etc. Taj Mahal is one of the most beautiful buildings of the world and is on the bank of river Yamuna. He built the Red Fort where he built many buildings like Diwan-i-Aam, Diwan-i-Khas, Moti Masjid, etc. Besides, he also built a throne for himself which was studded with diamonds and is known as Takht-e-Taus. Because of all these features, he is called the ‘Prince of Architecture’.

II. Fill in the blanks :

Question 1.
The Qutab Minar was completed by _________
Answer:
Qutab-ud-din Aibak/Iltutmish

Question 2.
_________ near Agra, was built by Akbar as his new capital.
Answer:
Fatehpur Sikri

Question 3.
The Buland Darwaja is situated in _________
Answer:
Fatehpur Sikri

Question 4.
Taj Mahal was built by in the memory of _________
Answer:
Shah Jahan/Mumtaz Mahal

PSEB 7th Class Social Science Solutions Chapter 12 Monumental Architecture

Question 5.
Jahangir built _________
Answer:
Akbar’s Tomb in Sikandra.

III. Write True or False for each statement:

Question 1.
Turks and Afghans introduced new styles and techniques of architecture in India.
Answer:
True

Question 2.
The temples at Khajuraho were built by the rulers of the Chandella dynasty.
Answer:
True

Question 3.
Ala-ud-din Khalji built a new capital at Siri.
Answer:
False

PSEB 7th Class Social Science Solutions Chapter 12 Monumental Architecture

Question 4.
Muhammad Tughlaq built Tughlaqabad.
Answer:
False

Question 5.
The Dravidian style of architecture was used in the Chola temples.
Answer:
True

IV. Activities

Question 1.
Collect pictures of the monumental architecture of the Mughal period and paste them in your notebook.
Answer:
Do it yourself.

Question 2.
Draw the Taj Mahal.
Answer:
Do it yourself.

PSEB 7th Class Social Science Guide Monumental Architecture Important Questions and Answers

Multiple Choice Questions

Question 1.
A Style of architecture in which roofs, doors and windows made by placing a horizontal beam across two vertical columns was known as
(a) Trabeate
(b) Superstructure
(c) Substructure
(d) None of these.
Answer:
(a) Trabeate.

PSEB 7th Class Social Science Solutions Chapter 12 Monumental Architecture

Question 2.
_________ were attached to the teinples, mosques, tombs and in buildings between 8th and 13th centuries.
(a) Substructures
(b) Baolis
(c) Gardens
(d) Chahar Bagh.
Answer:
(b) Baolis.

Question 3.
Who constructed Kandariya Mahadeva Temple?
(a) Rajarajadeva King
(b) King Srimara Shrivallabha
(c) King Dhangadeva
(d) King Sena-I.
Answer:
(c) King Dhangadeva.

Question 4.
Who destroyed the temple of Somnath?
(a) Muhammad Ghori
(b) Mahmud Ghaznavi
(c) Sena-I
(d) Sena-II.
Answer:
(b) Mahmud Ghaznavi.

Question 5.
Which of these Mughal emperor was personally interested in art and architecture?
(a) Akbar
(b) Jahangir
(c) Shahjahan
(d) All of these.
Answer:
(d) All of these.

PSEB 7th Class Social Science Solutions Chapter 12 Monumental Architecture

Question 6.
Who was a great lover of construction of buildings?
(a) Shahjahan
(b) Mahmud Ghaznavi
(c) Babur
(d) Humayun.
Answer:
(a) Shahjahan.

Question 7.
Who built the Taj Mahal?
(a) Babur
(b) Akbar
(c) Shahjahan
(d) Jahangir.
Answer:
(c) Shahjahan.

Question 8.
Who described his interest in planning and laying out formal gardens, placed within rectangular walled enclosures and divided into four quarters by artificial channels?
(a) Shahjahan
(b) Babur
(c) Akbar
(d) Humayun.
Answer:
(b) Babur.

Question 9.
Who constructed court in Red Fort which emphasised connection between royal justice and imperial court?
(a) Babur
(b) Akbar
(c) Shahjahan
(d) Jahangir.
Answer:
(c) Shahjahan.

PSEB 7th Class Social Science Solutions Chapter 12 Monumental Architecture

Question 10.
Who built the city of Fatehpur Sikri?
(a) Akbar
(b) Shahjahan
(c) Babur
(d) Jahangir
Answer:
(a) Akbar.

Match the following columns :

Question 1.

A B
1. Lingaraja Temple (i) Bhubneshwar
2. Birhadeshvara Temple (ii) Delhi
3. Adhai Din Ka Jhonpara (iii) Fatehpur Sikri
4. Adina Masjid (iv) Khajuraho
5. Humayun’s Tomb (v) Madurai
6. Moti Masjid (vi) Agra.
7. Red Fort (vii) Tanjavur
8. Taj Mahal (viii) Ajmer.

Answers :

A B
1. Lingaraja Temple (i) Bhubneshwar
2. Birhadeshvara Temple (vii) Tanjavur
3. Adhai Din Ka Jhonpara (viii) Ajmer.
4. Adina Mosque (ii) Delhi
5. Humayun’s Tomb (ii) Delhi
6. Moti Masjid (vi) Agra.
7. Red Fort (ii) Delhi
8. Taj Mahal (vi) Agra.

Short Answer Type Questions

Question 1.
Which is the largest statue in the world?
Answer:
In Karnataka, a statue of Sharavanbelgola is located at Gomateshvara.

Question 2.
Give a list of temples of North India built from 806-1200 A.D.
Answer:

  1. Jagannath Puri Temple.
  2. Lingaraja Temple of Bhubneshwar.
  3. Sun temple at Konark.
  4. Tejpal Temple at Mount Abu.

PSEB 7th Class Social Science Solutions Chapter 12 Monumental Architecture

Question 3.
Describe briefly the Birhadeshvara temple of Tanjavur.
Answer:
It is a magnificent example of temple construction in South India. This Lord Shiva temple was built by King Raj Raja I. The main door of this temple is known as ‘Gopuram’. Its height is almost 94 meters.

Question 4.
Describe briefly the Kailash temple at Ellora.
Answer:
This temple is a beautiful example of the building art of Rashtrakuta kings. It was built by Rashtrakuta King Krishna I. This temple has been cut out of rocks. This temple is considered one of the wonders of the world.

Question 5.
Name two buildings built by Mughal Emperor Jahangir.
Answer:
In Sikandara he built Akbar’s Tomb and in Agra, he built Itmad-ud-Daulah’s Tomb.

Question 6.
Shah Jahan built many other buildings besides Taj Mahal. Describe briefly.
Answer:
Shah Jahan built the following buildings besides Taj Mahal:
1. Red Fort: It was built by Shah Jahan in Delhi near the banks of Yamuna in 1639. It is made of red stone. In this castle, there are many beautiful buildings called ‘Rang Mahal’, ‘Diwan-i-Aam’, ‘Diwan-i-Khas’, ‘Shah Burj’ and ‘Khwab-Gah’. It has been decorated with valuable stones, diamonds, gold and silver.

2. Moti Masjid: Moti Masjid has been bruit by Shah Jahan in the Red Fort of Agra. It is made of marble and the expenditure was 3 lakh rupees.

3. Musamman Burj: It is also made of marble. It is very beautiful and looks clearly from Taj Mahal.

4. Shahjahanabad: In 1639 A.D., Shah Jahan founded Shahjahanabad. To make this city, skilled workers were brought from far and wide.

5. Jama Masjid: This is one of the biggest mosques of India. It took 10 years to build it.

6. Jahangir’s Tomb: This tomb was built in Shahdara (Pakistan). It was decorated with marble.

7. Peacock Crown Throne of Shah Jahan: It is placed in Diwan-i-Khas. It is known as Takhat-i-Taus. It is made up of marble. It took 7 years to build it and one crore was the expenditure. In 1739 A.D., Nadir Shah took it to Iran.
Besides the above, Delhi’s Shalimar Bagh and Kashmir’s Wazir Bagh are also very famous.

PSEB 7th Class Social Science Solutions Chapter 12 Monumental Architecture

Question 7.
How did regional kingdoms contribute to architecture?
Answer:
In regional kings we can name the Bahmani kings and Vijaynagar kings :

  1. The Bahmani rulers built Jama Masjid, Char Minar, Madrasa of Mahmud Gawan. In Gulbarga, the tomb of Ferozshah is a beautiful example of building style.
  2. The kings from Vijaynagar made Hajara Rama and Vithal Swami Mandir.
  3. Besides Bahmani and Vijaynagar kings the Jaunpur ruler also built important monuments. The Atala mosque built by them is very famous.

Question 8.
Describe the main features of North India’s temples.
Answer:
From 800 to 1200 A.D., many temples were built in north India. The features are as under :

  • These temples were built in Nagar style. The Khajuraho Temple of Madhya Pradesh is a magnificent piece of Nagar art style.
  • The Tejpal Temple of Mount Abu in Rajashan and other temples have been built in white marble. These temples show the best artistic skill.
  • On the internal sidewalls of the temples beautiful statues have been carved. Whereas, outer side walls are plane.

Question 9.
Write short notes on the following :
1. Monuments constructed by Akbar.
Answer:
Monuments constructed by Akbar. Akbar was a lover of architecture. He built many forts and buildings where red stone was used. The buildings built by Akbar include Jama Masjid, Panch Mahal, Diwan-i-Khas and Diwan-i-Aam. After the victory of Gujarat, he built ‘Buland Darwaza’. His buildings are built on the style of Irani and Hindu building style.

2. Importance of temples in South India.
Answer:
Importance of temples in South India :

  • Raj Rajeshwar Temple built by Chola King Rajraja.
  • Gangaikondcholpuram temple built by the Chola king Rajendra I.
  • The Kailash Temple in Ellora built by Rashtrakuta rulers.
  • Brahdeshwar Temple in Tanjavur.

3. The Taj Mahal.
Answer:
The Taj Mahal. Taj Mahal is the most beautiful building built by Mughal emperor Shah Jahan. It is located on the banks of river Yamuna. It was built by Shah Jahan in the memory of his beloved wife Begum Mumtaz Mahal. To built the Taj Mahal almost 20,000 workers worked for twenty two years and almost 3 crores were spent as expenditure. Taj Mahal is a beautiful mixture of many building styles. It is made of white marble and decorated with almost 20 types of valuable stones brought from different countries. Because, of its beauty it is counted among the seven wonders of the world.

Question 10.
Make list of the monuments constructed during the Delhi Sultanate.
Answer:
The description is as follows :
1. Monuments by the slave dynasty: Qutab-ud-din built a mosque named Quwat- ul-Islam in Delhi. It has writings from the Holy Quran. In Ajmer he built a mosque named Dhai-Din-Ka-Jhompra. He also started the construction of Qutab Minar near Mahroli in Delhi. But because of his death, the construction could not be completed. Afterwards, his successor Iltutmish completed it. The 70-metre high building has five storeys.

2. Monuments in the period of Ala-ud-din Khalji: The ‘Alai Darwaza’ is the most famous building built by Ala-ud-din Khalji. This door is made up of red stone and white marble. Ala-ud-din Khalji also built a palace with 1000 pillars, Hauz-i- Khas, and a mosque named Jamait Khana.

3. Monuments by Tughlaq rulers:

  • Giasuddin Tughlaq built a city called Tughlaqabad near Delhi.
  • Muhammed-bin-Tughlaq built a city named Jahanpanah.
  • The cities founded by Ferozshah Tughlaq include Firozabad, Firoza, Hisar, and Jaunpur. He built many mosques, schools, bridges, etc.

4. Buildings by Lodhis and Sayyid: These Sultans made tombs of Mubarak Shah and Muhammad Shah. The tomb of Sikandar Lodhi, Bara Gumbad, etc, was built during the Lodhi period.

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

Punjab State Board PSEB 7th Class Science Book Solutions Chapter 5 Acids, Bases and Salts Textbook Exercise Questions and Answers.

PSEB Solutions for Class 7 Science Chapter 5 Acids, Bases and Salts

Science Guide for Class 7 PSEB Acids, Bases and Salts Intext Questions and Answers

Think and Answer (Textbook Page No. 54)

Question 1.
What will be the colour of basic solution after the addition of pehnolphthalein?
Answer:
Adding phenolphthalein to the alkaline solution turns its colour to pink.

Question 2.
Name the products of neutralisation.
Answer:
In the process of neutralisation salt and water are produced in the form of products.

PSEB 7th Class Science Guide Acids, Bases and Salts Textbook Questions and Answers

1. Fill in the blanks:

(i) Acids are …………….. in taste.
Answer:
sour

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

(ii) Litmus and turmeric extract are …………….. indicators.
Answer:
natural

(iii) Phenolphthalein is ………………………… in acidic solution.
Answer:
pink

(iv) Reaction between an acid and a …………………… is called neutralisation reaction.
Answer:
alkali (Base)

(v) Ant’s sting has ………………….. acid.
Answer:
formic

(vi) Excess secretion of hydrochloric acid in stomach, is called ……………………….. .
Answer:
indigestion

(vii) Milk of magnesia is used in case of ……………………. .
Answer:
acidity

2. Match the Column ‘A’ with Column ‘B’:

Column ‘A’ Column ‘B’
1. Red litmus changes to blue in (a) Neutralisation
2. Blue litmus changes to red in (b) Zinc Carbonate
3. Reaction between acid and a base (c) Basic solution
4. Formic acid (d) Antbite
5. Calamine (e) Acidic Solution

Answer:

Column ‘A’ Column ‘B’
1. Red litmus changes to blue in (c) Basic solution
2. Blue litmus changes to red in (e) Acidic Solution
3. Reaction between acid and a base (a) Neutralisation
4. Formic acid (d) Antbite
5. Calamine (b) Zinc Carbonate

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

3. Choose the Correct Answer:

Question (i)
Vinegar contains :
(a) acetic acid
(c) citric acid
Ans.
(a) acetic acid .

Question (ii)
Tamarind contains :
(a) acetic acid
(b) lactic acid
(c) citric acid
(d) tartaric acid
Answer:
(d) tartaric acid

Question (iii)
The example of natural indicator is
(a) Litmus
(b) Turmeric extract
(c) China rose petals
(d) All the above
Answer:
(d) All the above

Question (iv)
The colour of blue litmus in acidic solution in :
(a) purple
(b) blue
(c) red
(d) pink
Answer:
(c) red

Question (v)
Amla contains :
(a) ascorbic acid
(b) quick lime
(c) calmine
(d) All the above
Answer:
(a) Ascorbic acid

4. Write True or False:

(i) Citric acid is found in tamarind.
Answer:
False

(ii) Ant’s sting has oxalic acid.
Answer:
False

(iii) Turmeric extract gives reddish brown colours in basic solution.
Answer:
True

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

(iv) Sodium hydroxide turns blue litmus red.
Answer:
False

(v) Organic matter is used to treat acidic soil.
Answer:
False

5. Very Short Answer Type Questions:

Question (i)
Which acid is secreted in our stomach ?
Answer:
Gastric acid is excreted in our stomach.

Question (ii)
Name any two ant acids.
Answer:
Names of two antacids :

  1. Magnesium Hydroxide,
  2. Baking Soda.

Question (iii)
What type of substances are used as ant bites ?
Answer:
Solution of calamine or baking soda is used to treat ant-stings.

Question (iv)
Name any two citric fruits.
Answer:
Names of Citrus Fruits :

  1. Orange,
  2. Lemon,
  3. Grapes.

Question (v)
Why is it essential to treat acidic products ?
Answer:
Factory and industry residues are naturally acidic. If thrown away directly without treatment, it can harm aquatic life. To neutralize them, some base is added to such wastes.

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

6. Short Answer Type Questions:

Question (i)
Name the source from which litmus solution is obtained. What is the use of this solution ?
Answer:
The solution of litmus is obtained from a plant called lichens found in nature. A strip of paper dipped in a solution of litmus is called litmus paper and the solution is called litmus solution. It is available as red and blue litmus.
Blue litmus turns red when dissolved in acidic solution and red litmus turns blue when dissolved in alkaline solution.

Question (ii)
Is the distilled water acidic/basic/neutral ? How would you verify it ?
Answer:
Distilled water is neutral. This is confirmed by the addition of litmus with which it gives green colour. The colour of Red litmus and blue litmus remain unchanged when added to distilled water showing that it is neutral in character.

Question (iii)
Describe the process of neutralisation with the help of an example.
Answer:
Neutralisation. The chemical reaction between an acid and an alkali is called neutralisation. As energy is released, salt and water are formed as products.
Acid + Alkali → Salt + Water + Heat (Energy)
Example : Hydrochloric Acid + Sodium Hydroxide → Sodium chloride + Water + Energy

Experiment: Fill a quarter of a test tube with dilute hydrochloric acid. Now add 2-3 drops of phenolphthalein solution (indicator) and note the color of the test tube solution. Now with the help of a dropper add a few drops of sodium hydroxide (alkali) in the test tube and gently shake the test tube. To the solution while stirring constantly, add Sodium hydroxide (alkali) solution till it turns light pink.
PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts 1
Now mix a drop of dilute Hydrochloric acid to it. You will notice that the color of the solution has disappeared (colourless) again. It is clear from this that phenolphthalein is pink in color as long as the solution is alkaline and the solution becomes colourless when the solution becomes acidic.

By mixing alkali solution with acid solution, they react with each other to neutralize the solution, i.e. the nature of acid and base gets cancelled out. This reaction is called Neutralisation.

Question (iv)
Name any two common acids and two common bases.
Answer:
Common acids. (1) Hydrochloric acid. (2) Sulphuric acid.
Common Bases. (1) Sodium hydroxide, (2) Calcium hydroxide

Question (v)
What are indicators ? Write their types and two examples of each.
Answer:
Indicators. Solution of substances that on reaction with acids, alkalis and neutral substances, give different colours, they are called indicators.
Types of indicators. There are two types of indicators:

  1. Natural indicators. These are indicators that are obtained from plants such as litmus, turmeric, China rose petals etc.
  2. Synthetic Indicators. These are indicators that are prepared in the laboratory, such as phenolphthalein and methyl orange etc.

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

7. Long Answer Type Questions:

Question (i)
State differences between acids and bases.
Answer:
Differences between Acids and Bases :

Acids Bases
1. They are sour in taste.

2. They change the solution of blue litmus to red.

3. They don’t seem like soap when touched.

4. It doesn’t change colour of phenolphthalein solution.

5. They react with bases to produce salt, water and heat.

1. They are bitter in taste.

2. They change solution of red litmus to blue color.

3. They appear like soap when touched.

4. They react with phenolphthalein solution to make it pink.

5. They react with acid to produce salt, water and heat.

Question (ii)
Name the acid present in : (1) Vinegar (2) tamarind (3) citrus fruits and (4) curd.
Answer:
Substance The name of the acid

1. Vinegar  1. Acetic acid
2. Tamarind  2. Tartaric acid
3. Citric fruit  3. Citric acid
4. Spinach  4. Oxalic acid
5. Yogurt  5. Lactic acid

Question (iii)
You are given hydrochloric acid solution, sodium hydroxide solution and water in three different bottles. How would you check which bottle has which compound ?
Answer:
1. Take three test tubes. Take a few drops of the solution from each bottle separately in these three test tubes. Now add three drops of phenolphthalein solution to each of these test tubes. The test tube in which pink colour is observed contains base (Sodium Hydroxide) while the colour will not change in the other two test tubes.

2. Wash the test tubes and again take 5-5 drops of each solution in three different test tubes as before. Now put two drops of blue litmus in these test tubes. The test tube in which the blue litmus turns red contains acid (Hydrochloric acid).

3. Now we know that the third test tube contains water in which red and blue litmus don’t show any change.
In this way, we can find out which solution is present in which bottle.

PSEB Solutions for Class 7 Science Acids, Bases and Salts Important Questions and Answers

1. Fill in the Blanks:

(ii) is used to cure indigestion.
Answer:

(iii) Treatment of soil acidity is done by adding
Answer:
Lime

(iv) on reaction with a solution of phenolphthalein turn it pink.
Answer:
Alkali

(v) In the process of Neutralisation and are produced as a products.
Answer:
Salt, water

2. Match the Column A with Column B:

Column ‘A’ Column ‘B’
(i) Gooseberries (a) Acetic acid
(ii) Indigestion (b) Quick lime
(iii) Vinegar (c) Milk of Magnesia
(iv) Treatment of acidic soil (d) Ascorbic acid

Answer:

Column ‘A’ Column ‘B’
(i) Gooseberries (d) Ascorbic acid
(ii) Indigestion (c) Milk of Magnesia
(iii) Vinegar (a) Acetic acid
(iv) Treatment of acidic soil (b) Quick lime

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

3. Choose the Correct Answer:

Question (i)
Curd tastes sour so it is :
(a) basic
(b) acidic
(c) salt
(d) None of these.
Answer:
(b) acidic.

Question (ii)
Bases are :
(a) sour
(b) saltish
(c) bitter
(d) Neither sour nor sweet.
Ans.
(c) bitter.

Question (iii)
The acid present in vinegar is :
(a) Formic acid
(b) Citric acid
(c) Acetic acid
(d) Lactic acid.
Answer:
(c) Acetic acid.

Question (iv)
The acid present in curd is :
(a) Acetic acid
(b) Formic acid
(c) Citric acid
(d) Lactic acid.
Answer:
(d) Lactic acid.

(a) Calcium hydroxide
(b) turns blue litmus paper to red.
(c) Magnesium hydroxide
(a) Calcium hydroxide.

Acidic solution:
(a) turns red litmus paper to blue
(b) turns blue litmus paper to red
(c) neither turns blue litmus paper to red nor red litmus to blue
(d) None of these.

4. State True or False:

(i) Nitric acid turns red litmus blue.
Answer:
False

(ii) Sodium hydroxide turns blue litmus red.
Answer:
False

(iii) Sodium hydroxide and hydrochloric acid neutralize each other and form salt and water.
Answer:
True

(iv) Indicator is a substance which shows different colours in acidic and basic solution.
Answer:
True

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

(v) Tooth decay is caused by the presence of a base.
Answer:
False

Very Short Answer Type Questions

Question 1.
Name different types of substances based on their chemical nature.
Answer:

  1. Acidic
  2. Basic
  3. Neutral.

Question 2.
Name few substances that contain natural acids.
Answer:
Curd, lemon juice, orange juice, vinegar.

Question 3.
Name few substances which are basic in nature.
Answer:
Washing soda, baking soda.

Question 4.
Name the substance which is used to test the nature of chemical compounds.
Answer:
Indicator.

Question 5.
Name few natural indicators.
Answer:
Turmeric, litmus, China rose petals.

Question 6.
Which acid is present in curd ?
Answer:
Lactic acid.

Question 7.
What is household name of Acetic acid ?
Answer:
Vinegar.

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

Question 8.
Amla is rich in which acid ?
Answer:
Ascorbic acid.

Question 9.
What is lime water ?
Answer:
It is calcium hydroxide, a base.

Question 10.
Name a base found in soaps.
Answer:
Sodium hydroxide.

Question 11.
What is use of Ammonium hydroxide ?
Answer:
For cleaning window glass panes.

Question 12.
What is source of litmus ?
Answer:
Lichens.

Question 13.
What are neutral substances ?
Answer:
Neutral Substances. The substances which do not change the colour of either blue or red litmus, are neutral substances.

Short Answer Type Questions

Question 1.
Write the properties of bases.
Answer:
Properties of Bases,

  1. Bases are bitter to taste.
  2. All alkalies have a slippery touch much like that of soap.
  3. Bases turn red litmus paper blue.
  4. Bases turn phenolphthalein solution from colourless to pink.

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts

Question 2.
Write the properties of acids.
Answer:
Properties of Acids.

  1. Acids turn blue litmus red.
  2. Acids contain hydrogen atom.
  3. Acids are sour in taste.
  4. Acids react with bases to form salt and water.

PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts 2

Question 3.
What is an indicator ? Name an indicator.
Answer:
Indicator. The chemicals or substances which give different colours with acids and bases, are known as acid-base indicators or simply indicators.
Phenolphthalein is another indicator which gives pink colour in alkaline solution and is colourless in acidic solution.

Question 4.
What is neutralization reaction ?
Answer:
Neutralization reaction. The process of treating an acid with an alkali/base to form a salt and water, is called neutralization reaction.
PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts 3

Question 5.
How the salts are formed?
Answer:
Salts. Salts are formed when an acid reacts with a base or salt is a compound which is formed by combination of acid with base.
PSEB 7th Class Science Solutions Chapter 5 Acids, Bases and Salts 4

Question 6.
Three liquids are given to you. One is hydrochloric acid, another is sodium hydroxide and third is a sugar solution. How will you identify them ? You have only turmeric powder.
Answer:
Turmeric powder is a natural indicator. With turmeric powder, turmeric strips are prepared which give different colour in three given liquids.

Question 7.
Blue litmus paper when dipped in a solution remains blue. What is the nature of the solution ? Explain.
Answer:
Acids turn blue litmus red while bases do not change the colour of blue litmus. Therefore, the given solution is base as it has not changed the colour of blue litmus paper.

Question 8.
Explain why :
(i) An antacid tablet is taken when you suffer from acidity.
(ii) Calamine solution is applied on skin when an ant bites.
(ii) Factory waste is neutralized before disposing it into the water bodies.
Answer:
(i) An antacid tablet is taken when you suffer from acidity. To neutralize acidity, antacid tablet such as milk of magnesia is taken because it contains Magnesium hydroxide (base) which neutralizes the effect of acids.

(ii) Calamine solution is applied on skin when an ant bites. Ant bite contains formic acid which gets neutralized by calamine solution (zinc carbonate).

(iii) Factory waste is neutralized before disposing it into the water bodies. Factory waste usually contains acids, so they have to be neutralized as they can kill aquatic animals and plants. Some basic substances are used to neutralize such wastes.

Long Answer Type Question

Question 9.
What are the uses of neutralization in our daily life? Explain in detail.
Answer:
Uses of Neutralisation in daily life:
(i) As Antacids.
We know that in human stomach acid is produced called as stomach acids which contain hydrochloric acid which helps in digestion of food. But too much of it can cause indigestion, abdominal pain, and heartburn, which is called acidity. To neutralize this excess acid, some mild alkali is used to relieve the pain. Such substances are called antacids, such as milk of magnesia (magnesium hydroxide), baking soda, etc.

(ii) As a treatment for insect stings.
Different species of insects such as; bees, wasps, spiders, and ants, etc. release formic acid in the body when they sting our body. The effect of formic acid can be reduced by neutralizing it with some mild alkali, such as baking soda or calamine solution.

(iii) As a treatment for soil acidity and alkalinity.
The presence of certain substances makes the soil more acidic or more alkaline. Excessive use of chemical fertilizers makes the soil acidic. Soil should be neutral for the proper growth and development of plants. Soils are tested and if it is acidic, it is treated with lime (calcium oxide), Quick lime (Calcium hydroxide), etc. But if the soil is alkaline, it is mixed with organic matter which releases acid and neutralizes the alkali present in the soil.

(iv) As a treatment for factory wastes.
Industry and factory wastes are naturally acidic. If it is thrown away directly, it can affect and harm aquatic life. Therefore, it is important to neutralize the acid present in that waste. So some alkali is added to treat it.

PSEB 7th Class Science Solutions Chapter 9 Soil

Punjab State Board PSEB 7th Class Science Book Solutions Chapter 9 Soil Textbook Exercise Questions and Answers.

PSEB Solutions for Class 7 Science Chapter 9 Soil

Science Guide for Class 7 PSEB Soil Intext Questions and Answers

Think and Answer (Textbook Page No. 103)

Question 1.
What is the chemical nature of the soil having pH is 3 ?
Answer:
The chemical nature of soil with pH value is acidic.

Question 2.
What is the chemical nature of soil having pH 10 ?
Answer:
Soil with pH value of 10 is alkaline.

PSEB 7th Class Science Solutions Chapter 9 Soil

Question 3.
Write down the pH of neutral soil.
Answer:
Neutral soils have pH of 7.

Think and Answer (Textbook Page No. 104)

Question 1.
In which type of soil rate of percolation is highest ?
Answer:
Sandy soils have the highest water leaching (leakage) rate.

Question 2.
Which soil has maximum water retention capacity ?
Answer:
Clay by soil has the highest water retention capacity.

Think and Answer (Textbook Page No. 106)

Question 1.
Why is soil tilled or ploughed ?
Answer:
Soil is ploughed to make the soil loose and porous.

Question 2.
What is the use of air present in soil ?
Answer:
The roots of the plants use the air present in the soil.

PSEB 7th Class Science Guide Soil Textbook Questions and Answers

1. Fill in the Blanks:

(i) The top layer of earth upto a depth of 30-40 cm where crops can grow is called ………………..
Answer:
Soil

(ii) A section of earth shows …………………. of soil.
Answer:
Layers

(iii) Acidic nature or alkaline nature of soil can be tested by using a …………………. .
Answer:
pH paper

(iv) ………………… has the finest particles which can even pass through muslin cloth.
Answer:
Clayey soil

PSEB 7th Class Science Solutions Chapter 9 Soil

(v) ………………. soil has least water retention capacity.
Answer:
sand

(vi) ……………….. soil is best for growing crops.
Answer:
Loamy and clayey

(vii) In western states of India like Gujarat and Maharashtra, the soil is of ………………… colour.
Answer:
Black

(viii) ………………… is used by potters for making earthen pots.
Answer:
Clay

(ix) The soil which is used for making cement is ………………….. .
Answer:
Clayey soil

(x) Bricks are made from ………………….. .
Answer:
sandy soil

2. State True or False:

(i) pH paper is used to test the acidic or alkaline nature of soil.
Answer:
True

(ii) Below a depth of 100 cm, the layer of earth is called soil.
Answer:
False

PSEB 7th Class Science Solutions Chapter 9 Soil

(iii) All crops grow better in sandy soil.
Answer:
False

(iv) Overgrazing of pasture lands is also responsible for soil erosion.
Answer:
True

(v) Mining can check soil erosion.
Answer:
False

(vi) Water can easily percolate through clayey soils.
Answer:
False

3. Match the Column ‘A’ with Column ‘B’:

Column ‘A’ Column ‘B’
1. Water can easily percolate through (a) Pollution of soil
2. This soil is best for growing cotton. (b) Soil erosion
3. Polythene, plastic and use of insecticides cause (c) Clay
4. Mining, overgrazing and deforestation cause (d) Black Soil
5. This soil is used in the manufacture of cement (e) Sandy Soil

Answer:

Column ‘A’ Column ‘B’
1. Water can easily percolate through (e) Sandy Soil
2. This soil is best for growing cotton. (d) Black Soil
3. Polythene, plastic and use of insecticides cause (a) Pollution of soil
4. Mining, overgrazing and deforestation cause (b) Soil erosion
5. This soil is used in the manufacture of cement (c) Clay

4. Choose the Correct Answer:

Question (i)
Which of these does not cause soil erosion ?
(a) Deforestation
(b) Building of check dams
(c) Grazing cattle
(d) Mining.
Answer:
(b) Building of check dams.

Question(ii)
Soil is polluted by:
(a) Rotation of crops
(b) Use of manure
(c) Use of insecticides and chemical fertilizers
(d) Using green manure.
Answer:
(b) Use of manure.

PSEB 7th Class Science Solutions Chapter 9 Soil

Question (iii)
Soil is not used for:
(a) Making insecticides
(b) Making check dams
(c) Making cement
(d) Making earthen pots
Answer:
(c) Making cement.

Question (iv)
Which of the following can check soil erosion ?
(a) Deforestation
(b) Afforestation
(c) Grazing of cattle
d) Mining.
Answer:
(c) Grazing of cattle.

Question (v)
Soil is used for.
(a) Making cement
(b) Growing crops
(c) Making Dams
(d) All of these.
Answer:
(c) Making Dams.

Very Short Answer Type Questions:

Question (i)
What is humus ?
Answer:
Humus. The dead and rotten leaves of plants or plants, insects or dead animals buried in the soil, animal dung, etc. combine to form organic matter of the soil called Humus.

Question (ii)
Name the organic constituents of soil.
Answer
Organic constituents of soil.

  1. Dead and decaying leaves of plants
  2. Bodies of dead animals
  3. Animal dung etc.

Question (iii)
Name the inorganic constituents of soil.
Answer
Inorganic components of Soil.

  1. sand,
  2. gravel,
  3. clay and
  4. mineral.

Question (iv)
What do you mean by loamy soil ?
Answer
Loamy soils. Soil whose particle size is between the size of sandy soil and clayey soil. This soil is best for crops.

Question (v)
Define soil erosion.
Answer:
Soil Erosion. Loss of topsoil due to strong winds, heavy rains, floods or other factors is called Soil erosion.

PSEB 7th Class Science Solutions Chapter 9 Soil

6. Short Answer Type Questions:

Question (i)
What is Soil Profile ?
Answer:
Soil Profile. A horizontal (or flat) Section passing through different layers of soil is called cut soil profile. The soil layout layers are as follows :

  1. organic layer,
  2. top soil,
  3. bottom soil. Soil,
  4. rock fragments,
  5. rocky solid floor.

Question (ii)
Draw a labelled diagram of a Soil Profile.
Answer:
PSEB 7th Class Science Solutions Chapter 9 Soil 1
Layers of Soil Profile:

  1. Mulch (organic layer)
  2. Top soil
  3. Sub soil
  4. Rock Fragments
  5. Bed rock

Question (iii)
How does sod get polluted ?
Answer:
Soil Pollution.
Soil pollution occurs due to the presence of unwanted and harmful substances in the soil. The soil is polluted by the following human activities:

1. Increased use of pesticides and chemical fertilizers. We use more pesticides and chemical fertilizers for higher crop yields. All these pesticides and chemical fertilizers remain in the soil due to their non-biodegradable nature which leads to soil contamination.

2. Waste of Industry. Many factories dumps their factory toxic waste in the surrounding areas, which results in soil pollution.

3. Polythene and plastic waste. Many chemicals are used in the manufacture of plastics and polythene. All plastics and polythene are non-biodegradable. When we throw plastic or polythene waste here and there then they remain lying in the soil due to which the soil becomes polluted.

Question (iv)
Why should we plant more bamboo plants ?
Answer:
Cattles need to be grazed in north-hilly and semi-mountainous areas. Grass is repeatedly eaten by cattle as a result of which the top layer of soil becomes bare and loose. As a result, the soil erodes quickly. Bamboo plants are very helpful in controlling soil erosion. So to prevent soil erosion plant as many plants as possible.

Question (v)
List the differences between clayey soil and sandy soil.
Answer:
Differences between clayey soil and sandy soil :

Clayey Soil Sandy Soil
(1) Particles of clayey soil are less than 0.005 mm in size. (1) Sand particles size vary from 0.05mm to 2mm.
(2) It contains humus. (2) It doesn’t contain humus.
(3) There is no empty space in its particles. (3) It has space in between its particles
(4) Doesn’t allow water to percolate. (4) It allows water to percolate through.
(5) It is used to make toys, utensils and sculptures (5) It is not used to make toys and utensils.
(6) It is sticky. (6) It is not sticky.

Question (vi)
What is a Check Dam ? Why is it built ?
Answer:
Check Dam.
Temporary or small dams are built on drains and canals in mountainous areas so that high speed water can be slowed down and used for irrigation. Doing so can help prevent soil erosion and maintain the fertility of the land. Apart from this, water is collected for irrigation for non-rainy days by stopping water during monsoon.

7. Long Answer Type Questions:

Question (i)
Explain how is soil formed ?
Answer:
Formation of Soil.
Many years ago the earth was hard and rocky. With the passage of time, the rocks were broken into small particles by earthquakes. Rain and river water turned these small particles into more fine particles and carried them away with them. This is how soil was formed.

PSEB 7th Class Science Solutions Chapter 9 Soil

Question (ii)
Explain the various factors responsible for soil erosion.
Answer:
Factors responsible for soil erosion:

  • Floods. Floods wash away the fertile topsoil. Sometimes the crops are washed away with flood water.
  • Wind and Storms. Very strong winds and storms blow away the topsoil and cause soil erosion.
  • Deforestation. When wild trees are failed down or the trees are uprooted, the soil becomes soft and loose and is easily washed away.
  • Over grazing. When animals repeatedly graze a grass field, the top layer of soil becomes bare and loose and is easily eroded.
  • Mining. Mining sand, gravel, or minerals become major fector for soil erosion.

Question (iii)
How is soil erosion checked ? Explain.
Answer:
The following steps are taken to check soil erosion:
(i) Planting of trees. Maximum number of local trees should be planted on barren hills and on flat lands grass should be grown. Bamboo plants are very, helpful in preventing erosion of the soil. Therefore, bamboo trees should be planted in hilly and semi-hilly areas.

(ii) Controlling the excavation of mines. Mining should be controlled. The digging should be done in such a way that the mining areas do not become pfond to landslides and soil erosion.

(iii) Grazing alternately. Animals should not be grazed continuously in the same area. After a while, the grazed place should be left empty and undisturbed and the animals should be grazed elsewhere.

(iv) Constructing check dams. Check dams should be constructed on small streams and drains in hilly areas. This will help to reduce soil erosion.

Question (iv)
Classify the soil on the basis of size of particles.
Answer:
Soil classification. Depending on the size of the particles, soil classified as sandy, rocky or loamy.

  • Clay. It is a soil whose particles are very fine, like dust and can also pass through muslin cloth. When water is added, it turns into mud and hardens on drying. Such clay is used to make pottery and utensils.
  • Sandy Soil. It’s particles are larger than clay particles. These particles cannot pass through the muslin cloth. Desert soils are usually sandy. Water is not retained in this type of soil.
  • Rocky Soils. Such soil particles are very large and can be picked by hand. Such particles cannot even pass through a filter.
  • Loamy Soil. The size of loamy soil particles is between the size of sand and clay particles. This type of soil is best for crops.

PSEB Solutions for Class 7 Science Soil Important Questions and Answers

1. Fill in the Blanks:

(i) The …………………. layer of earth in which crops can be grown is called soil.
Answer:
upper most

(ii) Particle size of ………………. soil lie between particle size of sand and clay.
Answer:
loam

(iii) The pH of ………………. soil lie between 8 to 14.
Answer:
Alkaline

(iv) Loss of top layer of soil is called ………………..
Answer:
soil erosion

PSEB 7th Class Science Solutions Chapter 9 Soil

(v) Inclusion of unwanted and harmful substances in the soil is called …………………
Answer:
soil pollution

2. Match the Column ‘I’ with Column ‘II’:

Column ‘I’ Column ‘II’
(i) A home for living organisms (a) Large particles
(ii) Upper layer of soil (b) All kinds of soil
(iii) Sandy soil (c) Dark in colour
(iv) Middle layer of the soil (d) Small particles and packed closely.
(v) Clayey soil (e) Lesser amount of humus

Answer:

Column ‘I’ Column ‘II’
(i) A home for living organisms (b) All kinds of soil.
(ii) Upper layer of soil (c) Dark in colour.
(iii) Sandy soil (a) Large particles.
(iv) Middle layer of the soil (e) lesser amount of humus
(v) Clayey soil (d) Small particles and packed closely.

3. Choose the Correct Answer:

Question (i)
The removal of top layer of soil by water and wind is called ……………………. .
(a) Soil pollution
(b) Soil erosion
(c) Soil profile
(d) Weathering.
Answer:
(b) Soil erosion.

Question (ii)
Which soil is the best for agriculture ?
(a) Loamy
(b) Sandy
(c) Clayey
(d) Sandy & Loamy.
Answer:
(a) Loamy.

Question (iii)
Which soil is better for pulse s ?
(a) Clayey
(b) Sandy
(c) Sandy and Loamy
(d) Loamy.
Answer:
(d) Loamy.

Question (iv)
Which layer of the soil is rich in minerals ?
(a) A-Horizon
(b) B-Horizon
(c) C-Horizon
(d) None of the above.
Answer:
(b) B-Horizon.

Question (v)
Which soil is well aerated ?
(a) Clayey
(b) Loamy
(c) Sandy and Loamy
(d) Sandy.
Answer:
(d) Sandy.

PSEB 7th Class Science Solutions Chapter 9 Soil

Question (vi)
The uppermost laver of earth’s crust is called
(a) Soil
(b) Wind
(c) Water
(d) None of the above.
Answer:
(a) Soil.

State True or False:

(i) Chemical fertilizers pollute the soil.
Answer:
True

(ii) From surface 30-40 cm deep layer of Earth in which plants can grow is called soil.
Answer:
True

(iii) The soil which contains iron salts is good for growing cotton.
Answer:
True

(iv) It only takes a few months for the top layer of soil to form.
Answer:
False

Very Short Answer Type Questions

Question 1.
What is soil ?
Answer:
Soil. The uppermost layer of earth’s crust is soil.

Question 2.
Are all the particles of soil of same size ?
Answer:
No, all the particles of soil are not of same size even the shape and colour of different soils is different.

PSEB 7th Class Science Solutions Chapter 9 Soil

Question 3.
On which factors, soil layers can be differentiated ?
Answer:
Soil colour, texture, depth and chemical composition.

Question 4.
Name the organisms found is soil.
Answer:
Worms, rodents, moles, beetles.

Question 5.
What is nature of bed rock ?
Answer:
Bed rock is hard in nature.

Question 6.
Which soil is well aerated ?
Answer:
Sandy soil.

Question 7.
Which soil is good for rice ?
Answer:
Clayey soil.

Question 8.
Which soil can retain more water ?
Answer:
Top soil.

Question 9.
Which type of soil is good for pulses ?
Answer:
Loamy soil.

PSEB 7th Class Science Solutions Chapter 9 Soil

Short Answer Type Qucstions

Question 1.
Explain the soil as a medium for growth of plants.
Answer:
Plants need soil to grow in as roots of plant take water and minerals from the soil. Soil also holds firmly the roots of plants, thus giving them support.

Question 2.
How can you call soil as a natural resource ?
Answer:
Soil as a natural resource. Soil is one of the most important natural land resource. Greenary on earth is possible only due to soil. Plants need soil to grow, for support and for nutrients.

Soil is main vital support to the living world. It provides the basic building material for shelter, bricks and mortar. Soil is also source of many elements such as aluminium, potassium etc. It also acts as good habitat for many organisms.

Question 3.
How is clayey soil useful for crops?
Answer:
Clayey soil has more power of retaining water. Clayey soil is rich in humus and is, therefore, very fertile. So it is good for crops.

Question 4.
Explain how soil pollution and soil erosion could be prevented.
Answer:
Prevention of Soil pollution:

  1. Ban on plastic and polythene bags.
  2. Treatment of waste before dumping it in the soil.

Prevention of soil erosion:

  1. Growing trees (cultivation)
  2. Crop rotation.
  3. Embankment of rivers.
  4. Afforestation.

Long Answer Type Question

Question 1.
Write uses of soil.
Answer:
Soil is the topmost layer of the earth’s crust. It is formed due to the breaking down of rocks by the action of heat from the sun, wind, and water.
Different uses of soil are:

  • Soil is one of the most important natural resources.
  • Soil supports the growth of plants by holding the roots firmly and supplying water and nutrients.
  • Soil is the home of many organisms.
  • Soil is essential for agriculture. Agriculture provides food, clothing, and shelter for all.
  • Soil is thus an inseparable part of our life.

PSEB 7th Class Social Science Solutions Chapter 6 Human Environment – Settlements, Means of Transport and Communication

Punjab State Board PSEB 7th Class Social Science Book Solutions Geography Chapter 6 Human Environment – Settlements, Means of Transport and Communication Textbook Exercise Questions and Answers.

PSEB Solutions for Class 7 Social Science Geography Chapter 6 Human Environment – Settlements, Means of Transport and Communication

SST Guide for Class 7 PSEB Human Environment – Settlements, Means of Transport and Communication Textbook Questions and Answers

I. Write down the answers to the following questions in approximately 1-15 words.

Question 1.
How does agriculture affect human settlement?
Answer:
Man was a nomad in the beginning. He used to look for his food in jungles. But when agriculture developed, he stayed at one place and thus settlements developed.

Question 2.
Where did people live, first of all?
Answer:
In the earlier times man would stay at the places, where water was easily available. Water fulfils many domestic and agricultural needs. So the early civilization developed near river valleys.

Question 3.
How does a topography of a place affect the development of human settlement of a place?
Answer:
It is easy to develop settlement on level surfaces. Here there are facilities of agriculture, means of transportation and communication. That is why most of the cities are in the northern plains of India. But on the uneven surfaces of the mountains there are limitations of rail, road transport, agriculture and as a result business is at a low level.

PSEB 7th Class Social Science Solutions Chapter 6 Human Environment - Settlements, Means of Transport and Communication

Question 4.
How are roadways important?
Answer:
Road transport is the earliest mode of transport. It gives us door-to-door service. Roads can also be constructed in mountainous regions. Construction of roads is also cheaper than building of railway tracks.

II. Write down the answers to the following questions in approximately 50-60 words.

Question 1.
Write down the importance of railways while explaining them.
Answer:
Railways are an important means of transportation. The travellers can travel in great numbers over long distances in a comfortable way with the help of railways. The materials can also be transported easily. Initially the rail engines were coal-driven, but now diesel engines and electric engines have come into existence.

Metro Railways: It is the underground railway network. Because of increasing population the road transportation becomes jam-packed. So underground railway network solves this problem. In Delhi Metro railway has become very important.

Main Railways of the World: In Europe and North America there is a great railway network. Now alongside the coastal areas of all continents, railways has been built. The railways of Russia (C.J.S.) joins St. Petersberg with Valadivastak. This railway line is known as Trans-Siberian Railway. It is the longest railway in the world. Similarly in Japan mainly the travellers travel by railways. Japan and France have almost the fastest running rails in the world. The bullet train of Japan runs with a speed of 500 km. per hr.

Importance of Railways: Railway is a major medium of land transport in modern times. Railways are important from economic, social and political point of view.

  • These help in the development of minerals of an area.
  • Railways carry raw materials to industrial areas and distribute manufactured goods to the market.
  • Railways promote trade.
  • It is convenient for long distances.

Question 2.
Write about the important waterways/ocean routes of the world.
Answer:
The waterways are the cheapest source of transportation.

The main waterways are as follows :

  1. North Atlantic Ocean ways
  2. Pacific Ocean ways
  3. Cape ways
  4. Sueze Canal ways
  5. Panama Canal ways.

Question 3.
Write about the internal waterways?
Answer:
The rivers and lakes are the internal waterways of the world.

Their names are as follows :

  1. In India the Ganges way, the Brahmaputra way and lakes located in Kerala.
  2. The Denub river of Europe joins middle and south Europe with Black sea.
  3. In China Yangste Kiang river.
  4. Amazon river in South America.
  5. There are five lakes in North America which join Canada and U.S.A.

PSEB 7th Class Social Science Solutions Chapter 6 Human Environment - Settlements, Means of Transport and Communication

Question 4.
World has become a Global Village with the development of Airways, illustrate the fact with example.
Answer:
Air transport. Since ancient times, men have wanted to fly. The first successful flight by aeroplane was made by the American Wright Brothers in 1903. Many developments during the 20th century have revolutionized air transport.

Air transport is the quickest means of transport. It needs no expenditure on the construction of air routes. It can cross physical barriers like mountains, oceans and deserts. But it is a costly means of transport. It is useful for transporting passengers, mails, food supplies and commodities of high value.

Factors affecting air transport :

  • Air routes generally follow great circles to fly over the shortest distance.
  • Air transport needs clear weather. Low clouds, fog, dust storms and snow are big handicaps.
  • The construction of aerodromes need level land.
  • Air transport requires huge capital.
  • The air transport needs adequate equipment and machinery.

PSEB 7th Class Social Science Solutions Chapter 6 Human Environment - Settlements, Means of Transport and Communication 1

In many countries of the world like London, Paris, Moscow, Tokyo, Saudi Arab and Dubai, very big airports have been established.

Question 5.
Which are the means of communication, what is the advantage of their development?
Answer:
The means of communication increase mutual coordination of human race. The voice of one person can be sent to another person or many persons very easily in any part of the worlds e.g with internet we can join our heads with the whole world. These days it is the cheapest source of interacting with others. With the help of Internet we can get information from any part of the world and about anything in the world. Moreover, postal services, telegram, telephones, cellphones radio, magazines and newspapers are the chief means of communication.

PSEB 7th Class Social Science Solutions Chapter 6 Human Environment - Settlements, Means of Transport and Communication

Question 6.
Write in detail about Suez Canal.
Answer:
Suez canal water way joins the European countries with South Asian Countries as well as African and Australian Continents. This canal also joins Equatorial sea with Red sea.

III. Activities:
With the help of Atlas and your teacher.

Question 1.
Show the Suez Canal and Panama canal on the world map.
Answer:

Question 2.
Show important airways on the world map.
Answer:
Do it with the help of your teacher.

PSEB 7th Class Social Science Guide Human Environment – Settlements, Means of Transport and Communication Important Questions and Answers

Multiple Choice Questions :

Question 1.
Which is not a means of communication?
(a) Telephone
(b) Books
(c) Newspaper
(d) Table.
Answer:
(d) Table.

Question 2.
Which mode of transport is most suitable to reach an island?
(a) Ship
(b) Train
(c) Car
(d) Aeroplane.
Answer:
(a) Ship.

PSEB 7th Class Social Science Solutions Chapter 6 Human Environment - Settlements, Means of Transport and Communication

Question 3.
Which type of road is constructed under the ground?
(a) Flyover
(b) Expressways
(c) Subways
(d) Roads.
Answer:
(c) Subways.

Question 4.
India ranks in development of railways in Asia :
(b) Second
(d) Fourth.
Answer:
(a) First.

Question 5.
Which is the fast means of communication?
(a) Telephone
(b) Telegraph
(c) Newspaper
(d) E-mail.
Answer:
(d) E-mail.

Fill in the Blanks :

Question 1.
________ sea and sea are the two seas joined by Suez canal.
Answer:
Red, Equatorial

Question 2.
Kolkata and Chennai are two ports on ________ coast of India.
Answer:
Eastern

Question 3.
Ganga is an ________waterway of India.
Answer:
Internal

PSEB 7th Class Social Science Solutions Chapter 6 Human Environment - Settlements, Means of Transport and Communication

Question 4.
Subways is a type of ________ constructed under the ground.
Answer:
Road

Question 5.
________ transport is the main means of international trade.
Answer:
Water.

True/False :

Question 1.
The surroundings of human race are called the environment.
Answer:
True

Question 2.
Delhi is a city where there is Metro railways.
Answer:
True

Question 3.
Denube river is interval waterways of Russia.
Answer:
False

Question 4.
Closely built area of houses are called compact settlements.
Answer:
True.

PSEB 7th Class Social Science Solutions Chapter 6 Human Environment - Settlements, Means of Transport and Communication

Question 5.
Internet is a means of communication.
Answer:
True

Very Short Answer Type Questions

Question 1.
What do you mean by environment?
Answer:
The surroundings of human race are called environment.

Question 2.
Describe the revolutions in the life of early man.
Answer:
Fire, clothing and settlements were the great revolutions in the life of early man.

Question 3.
Why did agriculture develop in River valleys?
Answer:
Because of fertile soil.

Question 4.
What do you mean by skyscrapers?
Answer:
The sky-touching multi-storey buildings.

Question 5.
What is the meaning of ‘Global Village’?
Answer:
Because of the fast means of transportation and communication, tne big world has become a small place and is called ‘Global Village’ these days.

PSEB 7th Class Social Science Solutions Chapter 6 Human Environment - Settlements, Means of Transport and Communication

Question 6.
Give the name of a city where there is Metro railways.
Answer:
Delhi.

Question 7.
Give the name of one Inter-continental Railways of Russia.
Answer:
The Trans-Siberian Railways.

Question 8.
Which are the cities combined by Trans-Siberian Railways?
Answer:
Saint Petersberg in the West with Vladivostok in the East.

Question 9.
Tell the name and speed of the fast moving train of Japan.
Answer:
Bullet train with a speed of 500 km per hour.

Question 10.
Where do we get waterways?
Answer:
In oceans, seas, rivers, canals, lakes, etc.

Question 11.
Name the biggest Railway in the world.
Answer:
Trans-Siberian Railway.

PSEB 7th Class Social Science Solutions Chapter 6 Human Environment - Settlements, Means of Transport and Communication

Question 12.
Name one internal waterways of Europe.
Answer:
Denube River.

Question 13.
Name one internal waterways of North America.
Answer:
Five Great Lakes.

Question 14.
Name two internal waterways of India.
Answer:
The Ganges and the Brahmaputra.

Question 15.
Which are the products sent through pipelines?
Answer:
Oil and gas.

Question 16.
How is electricity sent at different places?
Answer:
Through electric grid.

Question 17.
Who discovered aeroplane?
Answer:
Wright Brothers of America.

Question 18.
Write the names of two ports on the eastern coast of India.
Answer:
Kolkata and Chennai.

PSEB 7th Class Social Science Solutions Chapter 6 Human Environment - Settlements, Means of Transport and Communication

Question 19.
Name two brand new means of communication.
Answer:
Internet and mobile phones.

Question 20.
Which are the two seas joined by Suez Canal?
Answer:
Red sea and equatorial sea.

Short Answer Type Questions

Question 1.
Why did the old civilizations develop in River Valleys?
Answer:
There was easy availability of water. The soil was fertile, development of agriculture was possible. Residential settlements were easy to be built on even surfaces. That is why thOe best examples come from Indus Valley (India) and Nile river valley civilization (Egypt).

Question 2.
What type of changes have taken place in human settlements?
Answer:
The group of houses is called human settlements. Before that it was nomadic life for the man. Then the huts and houses were built. After that skyscrapers and multi-storey flats and buildings came into existence.

Question 3.
Why did the man settle? Give four reasons.
Answer:

  1. Increase in population.
  2. Development in industries.
  3. Development in agriculture.
  4. Industrial development.

Question 4.
The cities with the means of transportation become important commercial centres. Why?
Answer:

  • Easy availbility of products.
  • Increase in commercial profitability.
  • Existence of cultural and trading institutions.
  • Development of rails, roads and ports.

PSEB 7th Class Social Science Solutions Chapter 6 Human Environment - Settlements, Means of Transport and Communication

Question 5.
Why do we need metro railways?
Answer:

  • There is lack of land for railway lines so underground is the best possible way.
  • Increase in population leads to increase in the number of travellers.
  • To save the cities from traffic congestion.

Question 6.
What is the importance of Trans-Siberian Railways?
Answer:
It is the longest railways of the world. It opens inter-continental route, it joins St. Petersberg and Vladivostok cities. On this long railway the transportation of coal, iron, wood and grains takes place.

Question 7.
Explain the advantages of the waterways. Why it is the cheapest means of transportation?
Answer:

  • It is good means for sea voyages.
  • Main means of international trades.
  • Cheapest means of transport, because fuel consumption is less and carrying capacity is more.
  • No expenditure on making waterways.
  • The cargo can be sent on large scale at less cost.

Question 8.
Describe the air services in India.
Answer:
In India the air services have an important role to play. Because of Indian Airline and other private domestic Airlines have joined all the important cities in India. The international flights of Air India and Indian Airlines transport Indian travellers to different parts of the world. The main air-ports are in the cities of Amritsar, Delhi, Kolkata, Mumbai and Chennai.

PSEB 7th Class Social Science Solutions Chapter 6 Human Environment - Settlements, Means of Transport and Communication

Question 9.
Name the different types of means of transport.
Answer:
There are three main types of transport.

  1. Land transport includes roads, railways
  2. Ocean transport includes inland waterways and ocean routes
  3. Air transport includes airways.

Question 10.
Why is the road transport easier?
Answer:
Road is a major medium of land transport. It is the cheapest and the quikest means of transport for shorter distances. The roads link the fields and farms to factories, and the goods can be delivered right to the doorsteps of the consumers. Roads can be constructed in rough and undulating terrain. Dense network of roads has been the basis of development in European countries.

Question 11.
Describe the importance of Railways.
Answer:
Railway is a major medium of land transport in modern times. Railways are important from economic, social and political point of view.

  1. These help in the development of minerals of an area.
  2. Railways carry raw materials to industrial areas and distribute manufactured goods to the market.
  3. Railways promote trade.
  4. It is convenient for long distances.

Question 12.
Give an account of man’s progress to the stage of permanent settlements.
Answer:
Man has an extraordinary ability to survive even in difficult environment. First he used to do hunting and food gathering. He moved from place to place and led a nomadic life. Invention of farming as well as tools helped him to devise methods to grow food at one place. Agriculture needed constant attention from growing to harvesting stage. Gradually the concept of permanent settlements took shape.

PSEB 7th Class Social Science Solutions Chapter 6 Human Environment - Settlements, Means of Transport and Communication

Question 13.
Give information about waterways of the world: Also give the names of the main ports of India.
Answer:
Main waterways of the world
The waterways are the cheapest source of transportation. The main waterways areas ahead :

  1. North Atlantic Ocean ways
  2. Pacific Ocean ways
  3. Cape ways
  4. Suez Canal ways
  5. Panama Canal ways.

Main ports of India. Kolkata, Chennai, Cochin, Goa, Kandala and Vishakhapatnam are the main ports of India.

Long Answer Type Questions

Question 1.
Examine the importance of Highways.
Answer:
Land transport includes paths, unmetalled and metalled roads and highways. Roads have been used by man since the earliest times. Land transport develops according to nature of the land. In modem times the use of cemented roads and automobiles has increased the importance of roads. Roads are tiie basis of civilization. Roads link the fields and farms to the factories, factories to markets, and the goods can be delivered right at the door steps of the consumer. Roads can be constructed in inaccessible areas where railways and waterways are not easy to construct.

Question 2.
“Transport and communications are necessary infrastructures for the economic advancement of a country.’ Explain.
Answer:
Transport and communications constitute the infrastructure for the growth and development of agriculture, industry and trade of a country.

  1. The production and exchange of agricultural products depend on means of transportation.
  2. Developed means of transport are essential for assembling raw material for different industries. The manufactured goods are sent to markets at a low cost of transportation.
  3. An efficient system of transport is essential for the growth of trade of country.

As a matter of fact, the developed means of transport are an index of a country’s
economic development. Transport and communications serve as ‘life lines’ of a country’s development. These can be compared to arteries and veins of a nation.

Question 3.
The expansion of the means of transport and communications is shrinking the world. Discuss.
Answer:
With the modern developments in transportation and communications, man has controlled time and distance. During the past 50 years, the world’s means of transport and communication have been revolutionised. These changes have been marked with more rapid movement from place to place.

The ocean transport has served as a global, unbroken link between distant lands. The development of air transport has reduced the element of time. The major countries of the world are connected by air routes. Air transport has conquered physical barriers. The inter-continental air routes over the oceans have linked different continents. These fast means of transport have brought different areas closer to each other. It appears as if the world is shrinking day by day and we are living in a’smaller world.

PSEB 7th Class Social Science Solutions Chapter 6 Human Environment - Settlements, Means of Transport and Communication

Question 4.
Describe the development of Air Transport.
Answer:
Air transport. Since ancient times, men have wanted to fly. The first successful flight by aeroplane was made by the American Wright Brothers in 1903.-Many developments during the 20th century have revolutionized air transport.

Air transport is the quickest means of transport. It needs- no expenditure on the construction of air routes. It can cross physical barriers like mountains, oceans and deserts. But it is a costly means of transport. It is useful for transporting passengers, mails, food supplies and commodities of high value.

Factors affecting air transport :

  • Air routes generally follow great circles to fly over the shortest distance.
  • Air transport needs clear wheater. Low clouds, fog, dust storm and snow are big handicaps.
  • The construction of aerodromes need level land.
  • Air transport requires huge capital.
  • The air transport needs adequate equipment and machinery.

Question 5.
What are the factors which affect the development of human settlement?
Answer:
A group of houses is called settlement. Men started moving from villages to cities. There are certain reasons like increase in population, development of business. Agriculture in river valley and industrial development are the main reasons responsible for development of human settlements.

The Main Factors:
1. Availability of water. People mostly love to live at those places where water is easily available. That is why river valleys became birth places of many civilizations
in the world, eg. Indus Valley Civilization. It developed in the valley of Indus river. Here we have got proofs of Kaccha/Pucca houses.

2. Even surfaces. The uneven surfaces do not attract human settlement because :
(a) Transportation is difficult.
(b) Agriculture is difficult.
(c) House construction is difficult.

But even surfaces have many facilities :
(a) It is easy to make roadways and railways.
(b) Agriculture is easy.
(c) The agriculture produced can be easily transported to other places.
(d) Many big cities and metros have developed in plains with even surfaces.

3. Natural beauty. Many cities have developed because of natural beauty. Here tourism is well developed. It is a source of employment for many people. The examples are Kashmir, Goa, Bangalore, etc.

4. Means of transport and communication. The improved means of transportation and communication help in the development of human settlement. It becomes easy to move people and products from one place to another. With communication we can sent messages to any part of the world. Thus, those places develop economically as well as socially.

PSEB 7th Class Social Science Solutions Chapter 6 Human Environment - Settlements, Means of Transport and Communication

Question 6.
Explain in detail about the waterways.
Answer:
1. North Atlantic waterway: It is the maximum used waterway. It combines western Europe, U.S.A. and Canada. The maximum trade in the world takes place through this way.
PSEB 7th Class Social Science Solutions Chapter 6 Human Environment - Settlements, Means of Transport and Communication 2
Suez Waterway

2. Pacific Ocean waterway: It combines North and South America with Asia and Australia.

3. Cape way: It was discovered by Vasco-De-Gama in 1498. This way joins western European countries and America with South Asia, Australia, and New Zealand. The importance of Cape way has decreased because of the construction of Suez Canal waterway.

4. Suez Canal waterway: This canal joins the equatorial sea with the Red sea. It joins the European countries with South Asian countries as well as African and Australian continents.

5. Panama Canal way: This canal comes out of Panama Republic. It combines the Atlantic ocean with the Pacific ocean. This lake also results in the coming together of western Europe and eastern U.S.A. with Western U.S.A. and western Asia.

Question 7.
What contribution have the means of transportation towards the development of human settlement?
Answer:
Different means of transport have helped in the evolution of settlements in ahead ways:

  1. Two neighbouring settlements or even those found far away from each other became attracted to each other.
  2. Trade led to the growth of commercial activities and culture.
  3. It led to faster development of transport and communication from the stage of domestication of animals and the invention of the wheel.
  4. Roadways provided door-to-door service, railways helped to move a large number of people and goods in bulk. Waterways provided the cheapest means of transport. Air transport is fast though costly also developed side by side.
  5. Apart from transport media and other communication networks became crucial links for exchanging knowledge and ideas.

PSEB 7th Class Social Science Solutions Chapter 5 Natural Vegetation and Wildlife

Punjab State Board PSEB 7th Class Social Science Book Solutions Geography Chapter 5 Natural Vegetation and Wildlife Textbook Exercise Questions and Answers.

PSEB Solutions for Class 7 Social Science Geography Chapter 5 Natural Vegetation and Wildlife

SST Guide for Class 7 PSEB Natural Vegetation and Wildlife Textbook Questions and Answers

I. Give answers to these questions in approximately 1-15 words.

Question 1.
What do you understand by natural vegetation?
Answer:
It means those herbs, trees and plants which grow on their own. Man has no contribution in it. The natural vegetation of some place depends upon the surface, types of soil, climate, etc.

Question 2.
In how many types natural vegetation can be divided?
Answer:

  1. Forest,
  2. Grasslands, and
  3. Thorny bushes.

Question 3.
Which are the goods we get from the forests?
Answer:
Many types of wood, cane, grass for making paper, gum, biroza, turpentine, the skin for dying leather, medical herbs, etc are received from forests.

Question 4.
How do the forests help us indirectly?
Answer:

  • These take carbon dioxide from atmosphere and release oxygen.
  • These are helpful in bringing rainfall and controlling the temperature.
  • They stop floods and soil erosion.
  • They help in the absorbtion of water by the earth.
  • The forests stop the expansion of deserts and provide natural habitat to wildlife.

PSEB 7th Class Social Science Solutions Chapter 5 Natural Vegetation and Wildlife

Question 5.
What will be the effect of the development of forests?
Answer:
There will be no wood and the world will become a big desert.

Question 6.
How man is disturbing the ecological balance?
Answer:
In order to make residential colonies and for obtaining agricultural land, man is deforesting, which is contributing towards damaging the ecological balance.

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

Question 1.
Which are the forests that are economically useful? Explain.
Answer:
The most important and commercially valuable forests are coniferous forests. These forests are known as severgreen forests. In Eurasia these are known as Taiga forests. The trees found here are Cheerh, Fur, Spruce. We can get soft wood from these trees, which is used for making pulp and paper.

Question 2.
Why are the monsoon forests called deciduous forests?
Answer:
These forests are found on less heated latitudes. The areas which has more rainfall in any climate, there these trees have broad leaves. Such type of forests are more in those areas where there is more rainfall, because of monsoon winds. The season where there is no rainfall these trees shed their leaves. These forests are important from commercial point of view. Because these are less dense and within human reach. We get building wood and fuel wood from these forests, but most monsoon forests have been cut to give way for residential colonies and agriculture.

Question 3.
Write about the temperate grasslands.
Answer:
The hot and cold grasslands are found in hot and cold areas where the grass does not grow enough but it is soft and dense, so it is very useful for cattle grazing. In Eurasia these grasslands are called stepese, in North America these are called prairies, in South America-Pampas, in South Africa weld and in Australia these are known as Downs.

Question 4.
Write about the hot desert vegetation.
Answer:
Hot desert vegetation is found mainly in African Sahara and Kalahari, the deserts of Arab and Iran, the Thar desert of India-Pakistan. In South America Autocama, and in North America there is California desert and North Mexico desert and in Australia there is western Australian desert. Because of excess heat and very low rainfall there is very less vegetation. Here only thorny bushes, small herbs and grasses are born. The vegetation has been so made naturally that which can tolerate excess heat and dryness. The roots are long and thick. So that the plants can get moisture from the depth of earth. The bark of the plants is thick, the leaves are also thick and silky so that water is not wasted through vaporization.

Question 5.
Why is it necessary to conserve forests?
Answer:
The forests have a great role to play in our life, these fulfil our many needs. The wood from forests is used as fuel, building, paper making, railway sleepers as well as for cloth making. The forests-help to bring rainfall, control floods and soil erosion. But because of the increase in population the consumption of forests is increasing, so the area under forests is also decreasing. We must take care about planting more and more trees.

III. Things to do :

Question 1.
Prepare a list of various types of trees grown in your school compound. Plant a few sapplings also, with the help of your teacher.
Answer:
Do it yourself.

PSEB 7th Class Social Science Guide Natural Vegetation and Wildlife Important Questions and Answers

Multiple Choice Questions :

Question 1.
Which is an example of biosphere reserve of India?
(a) Corbett Park
(b) Kawal
(c) Pochmari
(d) Guindy.
Answer:
(c) Pochmari.

PSEB 7th Class Social Science Solutions Chapter 5 Natural Vegetation and Wildlife

Question 2.
Which type of forest does sundari tree?
(a) Tropical evergreen
(b) Tropical thorn & scrubs
(c) Tropical deciduous
(d) Mangrove.
Answer:
(d) Mangrove.

Question 3.
What thing restricts the forests of tropical evergreen?
(a) Temperature
(b) Rainfall
(c) Air pressure
(d) Air current.
Answer:
(b) Rainfall.

Question 4.
A change in height also changes the :
(a) Climate
(b) Natural vegetation
(c) Weather
(d) All of the above.
Answer:
(d) All of the above.

Question 5.
Which of the following type of forests called Taiga?
(a) Coniferous
(b) Tropical
(c) Temperate
(d) Deciduous.
Answer:
(d) Deciduous.

Fill in the Blanks :

Question 1.
There is variation in ______ from one area to another due to temperature and moisture variations.
Answer:
Vegetation

PSEB 7th Class Social Science Solutions Chapter 5 Natural Vegetation and Wildlife

Question 2.
In the ______ forests monkey and langoor are found.
Answer:
Tropical, Deciduous

Question 3.
The ______ forests are found between 10°N to 10°S Latitudes.
Answer:
Equatorial

Question 4.
National park covers a ______ area.
Answer:
Large

Question 5.
______ and continents in a combined form are called Eurasia.
Answer:
Europe, Asia.

True / False :

Question 1.
Coniferous forests are dominated by softwood trees.
Answer:
True.

Question 2.
Temperate grasslands are level and plains.
Answer:
True.

Question 3.
Taiga forests are conical in shape.
Answer:
True.

Question 4.
Praries is in South Africa.
Answer:
False

Question 5.
Some plants have very long roots to reach the underground water.
Answer:
True.

Very Short Answer Type Questions

Question 1.
Which are the industries dependent upon the forest wood?
Answer:
Many industries are dependent upon forest wood. These include furniture, sports goods, ships, railway bogeys, paper, plywood, packing boxes, etc.

Question 2.
What are the three factors which affect the varieties of forests?
Answer:

  1. Rainfall,
  2. Climatic conditions,
  3. Temperature.

PSEB 7th Class Social Science Solutions Chapter 5 Natural Vegetation and Wildlife

Question 3.
What is Eurasia?
Answer:
European and Asian continents in a combined form are called Eurasia.

Question 4.
Where is forest wood used mainly?
Answer:
Mainly it is used as fuel i.e. 50%, 33% is used in building, construction and the balance is in other works.

Question 5.
Write some steps for the protection and care of forests.
Answer:

  1. Care should be taken that the forest should not catch fire.
  2. Deforestation should be followed in a limited manner. Along side there should be afforestation also.
  3. The various types of pests and diseases should be removed so as not to destroy the forests.
  4. More and more trees should be planted around canals, ponds, rivers, roads and railway lines.
  5. There should be less use of wood for fuel purpose. Instead we should use sun energy and cow dung gas.
  6. Even in building, instead of wood there should be the use of some alternative material.

Question 6.
Mention the uses of coniferous forests.
Answer:
Coniferous forests are dominated by softwood trees. These woods are very useful for making pulp, which is used in the making of paper and newsprint. Match boxes and packing boxes are also made from softwood.
PSEB 7th Class Social Science Solutions Chapter 5 Natural Vegetation and Wildlife 1

Question 7.
Why the tropical evergreen forests in Brazil are called lungs of the earth?
Answer:
The tropical evergreen forests in Brazil are so extensive that they produce enough oxygen which can be used by the living beings.

Question 8.
List some typical animals lives in the Tropical rain forest.
Answer:
Anaconda, monkey, lemurs, apes, lizards and some kind of frogs are typical to tropical rain forest.

PSEB 7th Class Social Science Solutions Chapter 5 Natural Vegetation and Wildlife

Question 9.
Name the local names of Tropical Grasslands.
Answer:
In Africa these are known as parkland, in Venezuela these are known as Laoess and in Brazil these are known as Pampas.

Question 10.
Write about the vegetation of Cold desert.
Answer:
In cold deserts when the snow melts for a short time some small flowery plants take root. In the northern parts grass like moss and Lichen grow.

Short Answer Type Questions

Question 1.
Why the equatorial forests are considered a skyscraper?
Answer:
Skyscraper means a very high rising multi-storey building. The equatorial forests also represent such a kind of scheme that is why equatorial forest are called skyscrapers :

  1. The uppermost storey is made up of 70m. high trees. Here sun and air both are available. We get both fruit and flower here.
  2. The storey under this is umbrella-shape. The branches of the trees get entangled and take the form of umbrella type roof. Here the sunlight is less.
  3. The lower most storey has branches which rise on the trees and get entangled with each other. The branches which cannot live without sunlight move upwards to get sunlight.
  4. At the lowest level, there is extreme darkness, there is no sunlight. The leaves are damaged and smelly the area is full of insects and pests.

Question 2.
What is known as food-chain? State the status of humans in this food-chain.
Answer:
The feeding relationship between various organisms in an ecosystem is known as food-chain. Green plants use sun’s energy to produce their food. The plant food is eaten by animals. As a result transfer of sun’s energy also takes place. Some animals also eat plant eating animals. Thus energy is transferred to second trophic level. Humans are placed at the top in this food-chain. They eat both plant as well as plant eating animals.
PSEB 7th Class Social Science Solutions Chapter 5 Natural Vegetation and Wildlife 2
Food Pyramid

PSEB 7th Class Social Science Solutions Chapter 5 Natural Vegetation and Wildlife

Question 3.
Give a brief account of Equatorial Forests.
Answer:
These forests are found in those areas which receive over 200 cm of rainfall.
These are also known as tropical rain forests.

Location: These forests are found in the Amazon basin of South America, Zaire basin of Africa, South East Asian countries such as Malaysia, Indonesia, Myanmar, Thailand, New Guinea and Western ghats.

Main features:

  • These trees have broad leaves and their wood is hard.
  • The trees do not shed their leaves at any particular time of the year.
  • The forest is thick and luxuriant with plenty of trees.
  • Trees of same species are scattered in distribution.

Animal Life: Large animals like elephants and rhinoceros are found only in relatively less dense parts of these forests. On the other hand, the animals that can live on trees or in “the water bodies are more numerous. Jaguar, puma, monkey, squirrels and insects are common.

Question 4.
Explain the typical features of Thorny vegetation.
Answer:
Lack of water, dry winds and high temperature make conditions difficult for plants. However, plants do grow in the deserts and are admirably adapted to the environment.

Main features:

  • The roots of some plants spread far and wide but just below the surface of the ground. They absorb the rain water before it soaks away underground. The roots also absorb the dew which forms on the ground at night.
  • Some plants have very long roots to reach the underground water. The roots of the acacia may go down 30 m or more in search of water.
  • The leaves are often shed or reduced and the plant becomes dormant and stops growing during the driest periods in order to survive.
  • The leaves of many plants are tiny, waxy, leathery or varnished to minimize loss of water.

Wildlife: Animals survive the drought and heat at the desert’through adaptation. The typical animals are lizard, snake, camel, etc.

Question 5.
Give a brief description of Temperate Grasslands.
Answer:
Temperate grasslands are level, treeless plains. They lie far away from the influence of the sea. Temperate Grassland are known by different names in different continents.

  • Pampas-Argentina
  • Prairie-North America.
  • Veld-South Africa
  • Steppe-Central Asia
  • Downs-Australia.

Main features :

  • The rainfall is not sufficient for trees to grow. Some trees are found on hill sides with more rainfall, or along rivers. Willows and polar are the common trees.
  • Short grass grows everywhere. Areas, where the rainfall is more than 50 cm, have a rich carpet of grass suitable for cattle rearing.
  • Areas that receive less than 50 cm of rainfall have coarse grass which is suitable for grazing only sheep and goats.
  • The appearance of the grassland varies with the season.

Wildlife: Rodents, such as the prairie dog of America the gerbil of Africa, the hamster of Eurasia and the widespread mole, retreat underground escape from predators and the summer heat.

PSEB 7th Class Social Science Solutions Chapter 5 Natural Vegetation and Wildlife

Question 6.
Describe the main features of Taiga forests.
Answer:

  • These forests are found in higher latitudes. (50°-70° N)
  • These are coniferous forests.
  • These are conical in shape.
  • These are tall softwood evergreen trees.
  • These trees are useful for making pulp for newsprint and paper.
  • Matchbox and packing boxes are made from these.
  • Chir, pine, cedar, are important trees.
  • Silver fox, mink, polar bear are common animals.

Question 7.
Write about the equatorial type of forest.
Answer:
The equatorial forests are found between 10° north and 10° south latitude. These forests are known as evergreen dense forests. On the equator there is high temperature the whole year and there, is more rainfall also. That is why dense forests are found here. The upper branches of these trees are combined in such a manner that these look like an umbrella. Even the sunlight cannot reach earth. There are many types of trees in these forests. Still these trees are not commercially profitable. The reason is that these forests are so dense that it is not possible to cut these off. South America, middle of Africa, south-east Asia and Medagaskar have big areas under these kinds of forests. In Australia and middle America these forests have covered smaller area. In South America-Brazil such forests are known as Selwas in Amazon Basin.

Long Answer Type Questions

Question 1.
Write in detail about the natural vegetation. :
Answer:
Natural Vegetation. It means those herbs, trees and plants which grow on their own. Man has no contribution on it. The natural vegetation of some place depends upon the surface, types of soil, climate, etc.

Parts of Natural Vegetation.

  1. Forest
  2. Grasslands, and
  3. Thorny bushes.

Detailed Description:
1. Forests: Forests are affected by quantity of rainfall, climatic distribution, temperature, etc. This type of vegetation is of three types:
1. Equatorial Forests: The equatorial forests are found between 10° north and 100 south latitude. These forests are known as evergreen dense forests.

On the equator there is high temperature the whole year and there is more rainfall also. That is why dense forests are found here. The upper branches of these trees are combined in such a manner that these look like an umbrella.
Even the sunlight cannot reach earth. There are many types of trees in these forests. Still these trees are not commercially profitable. The reason is that these forests are so dense that it is not possible to cut these off. South America middle of Africa, south-east Asia and Medagaskar have big areas under these kind of forests. In Australia and middle America these forests have covered smaller area. In South America-Brazil such forests are known as Selwas in Amazon Basin.

2. Monsoon Forests. These forests are found on less heated latitudes. The areas which has more rainfall in any climate, there these trees have broad leaves. Such type of forests are more in those areas where there is more rainfall, because of monsoon winds. The season where there is no rainfall these trees shed their leaves. These forests are important from commercial point of view. Because these are less dense and within human reach. We get building wood and fuel wood from these forests, but most monsoon forests have been cut to give way for residential colonies and agriculture.

3. Coniferous Forests. The most important and commercially valuable forests are coniferous forests. These forests are known as evergreen forests. In Eurasia these are known as Taiga forests. The trees found here are Cheerh, Fur, Spruce. We can get soft wood from these trees, which is used for making pulp and paper.

2. Grasslands. The hot and cold grasslands are found in hot and cold areas where the grass does not grow enough but it is soft and dense, so it is very useful for cattle grazing. In Eurasia these grasslands are called stepese, in North America these are called prairies, in South America—Pampas, in South Africa weld and in Australia these are known as Downs.

3. Thorny Bushes. Hot desert vegetation is found mainly in African Sahara and Kalahari, the deserts of Arab and Iran, the Thar desert of India-Pakistan. In South America Atacama, and in North America there is California desert and North Mexico desert and in Australia there is western Australian desert. Because of excess heat and very low rainfall there is very less vegetation. Here only thorny bushes, small herbs and grasses are born. The vegetation has been so made naturally that which can tolerate excess heat and dryness. The roots are long and thick. So that the plants can get moisture from the depth of earth. The bark of the plants is thick, the leaves are also thick and silky so that water is not wasted through vaporization.

PSEB 7th Class Social Science Solutions Chapter 5 Natural Vegetation and Wildlife

Question 2.
Write about the care and protection of wild animals. Describe the role of wild animals in ecological balance.
Or
What is the role of wildlife in maintaining ecological balance?
Answer:
Conservation of Wildlife. India is rich in wildlife. There are about 81,000 known species of animals. She has 2500 species of fish and 1200 species of birds. But many of these species have been destroyed by man. Many rare species have become extinct in India. Our rich wildlife is a rich heritage formed through centuries. It must be preserved. Many of the species are found only in India such as swamp deer, the one- homed rhinoceros, Kashmir stag, Nilgai, etc. These rare species are in danger of extinction. Wildlife Act provides for the protection and conservation of these species. For this, zoos, national parks, bio-reserves and tiger reserves have been established in India.

The wildlife week is celebrated in the first week of October.
Difference between National Park and Sanctuaries

National Park Govt. Sanctuaries
1. A national park is a reserved area meant for preserving natural vegetation, wildlife and natural beauty. 1. A Govt, sanctuary is a reserved area meant for the preservation and development of endangered species.
2. It covers a large area. 2. It covers a small area.
3. Corbett National Park is an example. 3. Kaziranga Sanctuary is an example.

Extinction of certain species of animals and birds: Various kinds of animals and birds are found in the Indian forests. Important among them are the elephants, tigers, leopards, lions, rhinoceros, deer, etc. Several species of animals have become extinct in our country due to their reckless hunting and clearing of forests. As a result, rhinoceros, leopards, lions must deer and the Great Indian Bustard are found only in a small number. We should preserve these precious assets of our country.

Protection of Wildlife: The ways to preserve wildlife are as follows :

  • We should not fall trees thoughtlessly so that the wildlife population may get shelter and increase in the forests.
  • We should not hunt animals and birds in the mating season.
  • There should be a total ban on the hunting of rare species of wild animals so that they may not get extinct.
  • We should co-operate with the government in its efforts to preserve wildlife.

PSEB 7th Class Social Science Solutions Chapter 4 Ocean

Punjab State Board PSEB 7th Class Social Science Book Solutions Geography Chapter 4 Ocean Textbook Exercise Questions and Answers.

PSEB Solutions for Class 7 Social Science Geography Chapter 4 Ocean

SST Guide for Class 7 PSEB Ocean Textbook Questions and Answers

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

Question 1.
Why does the ocean water salty?
Answer:
Many salts are mixed in seawater. That is why the seawater is salty.

Question 2.
Why there is a dense fog near Newfoundland?
Answer:
Near this place, there is a meeting of the warm gulf stream and cold labrador current. So, there is a blanket of dense fog.

Question 3.
Explain the route of Gulf-stream current.
Answer:
The gulf-stream starts from Mexico gulf and reaches the Newfoundland Islands.

Question 4.
Write down the main ocean currents of North Atlantic Oceans Cycle.
Answer:
North equatorial stream, the Kurushivo stream, North Pacific stream, the California stream.

PSEB 7th Class Social Science Solutions Chapter 4 Ocean

Question 5.
What do you understand by Tsunami?
Answer:
Tsunamis are high tidal waves (30 metres high) caused by earthquakes in oceans. On 26th December, 2004; an earthquake occurred in Indian ocean. Its focus was near Indonesia. It caused Tsunamis in Indian ocean. These waves destroyed property worth millions of rupees. About 2 lakh persons died in Indonesia, Thailand, India and Sri Lanka. In India, most affected areas were Andaman Nicobar islands, Tamil Nadu coast, and eastern coast.

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

Question 1.
What is the difference between Spring Tide and Neap Tide?
Answer:
The periodical vertical rise and fall of the surface of the sea water is called a tide. The rising of water is called the high tide or up tide while the falling of water is known as low tide or down tide.

Tides are caused by the gravitational pull of the moon and to some extent, the sun. Tides are useful to us as they help in navigation and fishing. At the high tide, the depth of the seas particularly gulfs, and bays increases. This enables the big ships to enter or leave the harbours easily. Due to high tides in the Hooghly river the depth of the water increases. As a result big ships enter and leave the Kolkata port which is situated on the bank of this river. Some ports such as Kandla in Gujarat and Diamond Harbour in West Bengal depend on the tides. Tides, at some places, take away the mud brought down by¬rivers and prevent silting of harbours. Thus tides make the rivers suitable for navigation.
PSEB 7th Class Social Science Solutions Chapter 4 Ocean 1
Formation of Tides

Question 2.
Differentiate between warm water ocean current and cold water ocean current.
Answer:

  • According to Ferral’s law, ocean currents move to their right in the southern hemisphere.
  • Warm currents move towards cold seas and cold currents move towards the warm seas.
  • In the lower latitudes, warm currents flow on the eastern shores and cold on the western shores.
  • In the higher latitudes, warm currents flow on the eastern shores and cold on the western shores.
  • Cold and warm currents meet along the convergence and move out along divergence.
  • Cold currents move as sun-surface currents and warm currents move as surface currents.

PSEB 7th Class Social Science Solutions Chapter 4 Ocean 2

Question 3.
Why are the ocean currents of Indian ocean not so definite and systematic?
Answer:
Unlike Atlantic and Pacific ocean, the ocean currents of Indian ocean are not so definite and systematic. It is because of the seasonal winds which flow in Indian ocean. In summer season, these winds blow in south-west direction and in winter season, these direction blow in north-eastern direction. Because of this change the ocean currents also change their direction.

PSEB 7th Class Social Science Solutions Chapter 4 Ocean

Question 4.
Tide is very useful for ships. How?
Answer:

  1. Because of tides the mud and the soil continue to flow out of the river mouth. As a result, there is no deposits of soil on such coastal ports and ships can come in the interior.
  2. Big and heavy ships wait for tides in the deep sea. When there is high tide the ships along with the high tides reach the ports. Once they unload the cargo, they again wait for the tides. So, that they can go back easily to the sea. The ports of Kolkata and London are such examples.

Question 5.
Why a spring tide occurs in full moon and no moon days?
Answer:
At the time of high tide the sea water is on the rise. It happens only on full moon night and without moon night. Because on these two days the sun, moon and earth are in a straight line. On this day, the sun and moon together attract the sea water upwards. Because of this double attraction the tides rise high and it is known as high tide condition.

Question 6.
How does the Gulf-stream affect the climate of Europe?
Answer:
The Gulf-stream is the most important warm current of the world. Its width is 400 km approximately. The speed of its water is 5 km/hr. Near Newfoundland it meets labradors cold streams. As a result, there is dense fog conditioh. Here, the fish are also found in excess quantities. After this, it moves towards Europe. Because of its impact the winter in North-West Europe is not so cold.

Question 7.
What is the difference between ocean waves and the ocean currents?
Answer:
The sea water continues its up and down movement. According to climatic positions, the speed sometimes increases and sometimes slows down and it produces waves. The water particles run up and down and it looks as if there are wrinkles on the surface of the sea.

Sometimes the ocean water takes a fix direction, then it is called oceanic current. In the ocean water leaves one place and moves towards the other place regularly. The speed of the current can be 2 km/hr to 10 km/hr.

PSEB 7th Class Social Science Solutions Chapter 4 Ocean

Question 8.
Write down a case study of a place that is affected by Tsunami.
Answer:
On 26th Dec, 2004 there were most dangerous Tsunami tides in Indian Ocean. These were created by an earthquake which came on the sea surface measuring 9 points on Richter scale. The epicentre of this earthquake was the western course of Indonesia. In a matter of a few hours these waves brought heavy destruction in 11 countries bordering Indian Ocean. There was a great loss of life and property and the effect was experienced from Africa to Thailand.

According to an estimated figure, there was a loss Of life and property worth Rs. 5322 crore in India. The worst affected were Tamil Nadu, Kerela, Andhra Pradesh and Pondicherry. More than 2 lakh people were killed and many more were injured.

PSEB 7th Class Social Science Guide Ocean Important Questions and Answers

Multiple Choice Questions :

Question 1.
Which is not a warm ocean current?
(a) Labrador current
(b) Gulf stream
(c) Venezuela
(d) Kuroshio.
Answer:
(a) Labrador current.

Question 2.
Which is a tidal port in India?
(a) Mumbai
(b) Chennai
(c) Kandla
(d) Cochi.
Answer:
(c) Kandla.

PSEB 7th Class Social Science Solutions Chapter 4 Ocean

Question 3.
The rythmic rise and fall of ocean water twice in a day is called :
(o) Tide
(b) Ocean current
(c) Wave
(d) Current.
Answer:
(a) Tide.

Question 4.
How much of total water is fresh water?
(a) 0.5%
(b) 1.0%
(c) 2.5%
(d) 3.0%. .
Answer:
(c) 2.5%

Question 5.
Peru’s current is :
(a) Cold stream
(b) Hot stream
(c) Dry stream
(d) Wet stream.
Answer:
(a) Cold stream.

Fill in the Blanks :

Question 1.
The currents can be divided into _________________ ocean and two main parts.
Answer:
Northern ocean and southern ocean

PSEB 7th Class Social Science Solutions Chapter 4 Ocean

Question 2.
Area of pacific ocean is _________
Answer:
16.6 crore sq. km

Question 3.
_________ ocean is longest and deepest ocean on earth.
Answer:
Pacific

Question 4.
The Falkland current is the main current of __________ ocean.
Answer:
South Atlantic

Question 5.
The gulf stream starts from ___________ gulf.
Answer:
Maxico.

True / False :

Question 1.
Tsunamis are high tidal waves caused by earthquake.
Answer:
True

Question 2.
Generally warm ocean currents originate near poles.
Answer:
False

Question 3.
Ocean currents are strong seismic waves.
Answer:
False

PSEB 7th Class Social Science Solutions Chapter 4 Ocean

Question 4.
Venezuela current is the main current of South Atlantic ocean cycle.
Answer:
True

Question 5.
Tides happens twice in 24 hrs.
Answer:
True.

Very Short Answer Type Questions

Question 1.
What do you mean by Ocean? Write its one feature.
Answer:
On the surface of earth, there are big storehouses of water which are known as oceans. The water of these oceans is salty.

Question 2.
What do you mean by tides?
Answer:
The ocean water twice rises to the coast and twice goes down towards the sea. This up and down movement of water is known as tide.

Question 3.
Why does high tide take place on a full moon night and without moon night?
Answer:
This happens because on these two nights the attraction of sun doubles up with the attraction of moon. Because of its double attraction the high tide takes place.

Question 4.
What are the three different speeds of ocean water?
Answer:
The ocean water has three speeds waves, currents and tides.

PSEB 7th Class Social Science Solutions Chapter 4 Ocean

Question 5.
Write any one difference between wave and current.
Answer:
In wave, the water goes up and down continuously but it does not take speed. On the contrary in the current, water moves from one place to another.

Question 6.
How many oceans are there on earth?
Answer:
There are five oceans on earth. Their names are :

  • Pacific ocean, Atlantic oceans, Indian ocean, Arctic ocean, Antarctic ocean.
  • All these oceans are” combined with each other. The water of one ocean mixes with the other.

Question 7.
Write the areas of oceans.
Answer:
table-2

Question 8.
What is the difference between fresh water and saline water?
Answer:
Fresh Water. Rainfall, melting snow, rivers, canal, water pumps, etc. give us fresh water.
Saline Water. Mostly found in oceans. The most salt is in Dead sea. It is surrounded by earth from all the sides.

Question 9.
What is the most important hot water stream in the world?
Answer:
The most important hot water stream in the world is Gulf Stream. It starts from Mexico Gulf and reaches Newfoundland Islands.

Question 10.
Why do the fishermen of Norway go deep into sea for fishing?
Answer:
There is the hot current of water which is called North Oceanic hot water current. It flows near the Norway Coast. So, the fishermen go deep into the sea for fishing.

PSEB 7th Class Social Science Solutions Chapter 4 Ocean

Question 11.
Why do the western ports of West European countries remain open during winters also.
Answer:
Because of the effect of North Oceanic warm current these ports do not freeze and remain open even during the winter season.

Question 12.
Why are there deserts in the places where the cold currents pass?
Answer:
Whenever some winds pass over the cold currents, then these become cold and dry. So, the closer regions become deserts.

Question 13.
What is the effect of oceanic currents on ship movement?
Answer:
The ships generally move in the direction of currents. It increases there speed and consumes less fuel.

Question 14.
Write down the main currents of South Atlantic ocean cycle.
Answer:
South Atlantic ocean has two main currents :

  1. The Falkland current and
  2. Venezuela current.

Short Answer Type Questions

Question 1.
What is the effect of oceanic currents on the climate of some countries?
Answer:

  1. The warm currents increased the temperature of their neighbouring areas and cold currents decrease the temperature of their neighbouring areas.
  2. The winds passing over warm currents absorb the humidity and bring rainfall on coastal areas. Whereas the winds passing over cold currents become cold and dry.

PSEB 7th Class Social Science Solutions Chapter 4 Ocean

Question 2.
What do you mean by wave? How is it created?
Answer:
The ocean water always remains up and down. The water particles keep on jumping and this makes the ripples on the surface of sea. These are called waves. The waves are created because of the speed of the winds. When winds passes over the sea they shake the surface of water. This shaking and shivering of water surface is called waves.

Question 3.
Why do the North Indian Oceanic currents flow in reverse directions during Summer and winter?
Answer:
The local winds have the greatest effect on the direction of the currents. The direction in which the winds blow for a longer period, the ocean water also takes the same direction. In the north-Indian ocean the winds move in reverse direction in summer and winter. So, the water current also has reverse direction during summer and winter.

Question 4.
Why does low tide come on the sevenfh and twenty-first of full moon night?
Answer:
On these two dates the Moon and the Sun make 90° turn with the Earth. As a result, both attract the sea water in reverse directions. Because moon is closer to-the sea, the water jumps more towards the moon. But because of counter attractions of sun the effect of moon’s attractions becomes very less and as a result the jump of water becames too low and it is called low tide.

Question 5.
What are tides and how are they caused?
Answer:
Along coasts, the water slowly rises up over the shore and slowly falls back again. When the water has risen to its highest level, covering much of the shore, it is at high tide. When the water falls to its lowest level, it is low tide.
PSEB 7th Class Social Science Solutions Chapter 4 Ocean 3
Tides

Tides are caused by gravitational pull of the moon, and to some extent the pull of the sun on the earth’s surface.

The moon exerts gravitational pull on the earth as it orbits around it. This has little effect on land which is solid and inflexible but it has a great effect on the ocean waters because water is liquid can freely move about.

PSEB 7th Class Social Science Solutions Chapter 4 Ocean

Question 6.
What are ocean currents?
Answer:
These are streams of water move along the surface of ocean in definite paths. Such more or less permanent streams of water which flow in a definite direction are known as ocean currents. These are like rivers in the ocean, thousands of kilometres in length and sometimes about 200 km wide. Ocean currents can be cold and warm.

Question 7.
Ocean water is salty. Why?
Answer:
Sea water is salty or saline. This is because the sea contains a great variety of salts and minerals in solution. These minerals are brought down by the rivers in the silt they carry. It is estimated that the ocean contains enough salt to cover the continents with a layer 100 metres thick.

Question 8.
The quality of water is deteriorating. Why?
Answer:
The quality of water is deteriorating due to water pollution. The following factors affect water pollution—Domestic sewage, industrial wastes, agricultural activities, thermal pollution and marine pollution.

Question 9.
Why is the earth called a watery planet? Describe the distribution of water on the earth.
Answer:
The earth is the only planet of the solar system which contains water in abundance. Hence it is called a ‘watery planet’. Three fourth of the earth’s total surface is covered with water.

Distribution: Oceans contain about 97 percent of the total water available on the earth’s surface. The remaining three percent is the fresh water found in the form of snow and ice on the ground and in lakes and rivers. ”

PSEB 7th Class Social Science Solutions Chapter 4 Ocean

Question 10.
How are oceans useful to us?
Answer:
Oceans are useful to us in the following ways :

  • They modify land temperature.
  • Oceans are the source of water vapour which forms clouds. These clouds cause rainfall on the earth.
  • Oceans are a major source of food for the mankind.
  • They are an .excellent means of transport for bulk cargo.

Question 11.
Give reasons, why the western harbours of Britain remain open even in winter season whereas the eastern harbours of North America situated at the same latitude remain frozen?
Answer:
The currents affect the climate of the country deeply. In winters, there are cold conditions in north west of Britain. But, the north atlantic sea current takes easternly direction under the impact of western winds. This warm current reaches Norway and Sweeden cold countries through the north-west of Britain. Because of the impact of warm currents the western ports of Britain remain open. But, in the absence of such a climate the eastern ports of North America remain frozen and closed.

Question 12.
What is ‘Sargasso Sea’ and how does it form?
Answer:
The currents of north Altantic sea start from the equator and go towards the north. These move forward along with American Coast and when these came back along the European Coast these mix with equotorial current and complete there clockwise circle. The part of north Atlantic sea which comes inside the circle is called Sargaso sea.

Long Answer Type Questions

Question 1.
Describe in detail the currents of Indian ocean. Show these on the map also.
Answer:
The circle of Indian ocean currents is not fixed or regular. The main reason is seasonal winds of this ocean. These winds change their directions with the change in season. With this, the direction of Indian ocean currents also change.

The currents can be divided into two main parts :

  1. Northern Ocean
  2. Southern Ocean.

PSEB 7th Class Social Science Solutions Chapter 4 Ocean 4

1. Northern Ocean:

  • South-West Monsoon Current. Under the impact of south-west monsoons, the Indian oceanic current starts from west and flows towards east, this is called South-West Monsoon Current.
  • North Equatorial Current. On the north of equator, the south-west equatorial current has east to west direction. It is a hot water stream.
  • North Eastern Monsoon Current. On the north of equator, the North Equatorial Current flows from east to west. It is a hot water stream.

2. Southern Ocean: In the South hemisphere, mostly the currents have a fixed route which is as follows :

  • Southern Current of Equator: It is a hot water stream which flows from east to west in the south of equator.
  • Mozambiq Current: It is a part of the southern current of equator. When it hits the eastern coast of Africa then it takes southward direction. It is a hot water current.
  • Agulhas Current: Before Malagasi islands, one branch goes towards south, it is called Agulhas Current.
  • Western Australian Current: The south Indian oceanic current hits the south-west coast of Australia and one part moves towards north. This is called Western Australian Current. This cold current, at last meets North equatorial current and completes the circle.

PSEB 7th Class Social Science Solutions Chapter 4 Ocean

Question 2.
Explain with diagram the formation of Tides.
Answer:
Tides are caused by the gravitational pull of the moon and to some extent the pull of the sun on the earth’s surface.
PSEB 7th Class Social Science Solutions Chapter 4 Ocean 5

  • The moon exerts a gravitational pull on the earth as it orbits around it. This has little effect on land which is solid and inflexible but it has a great effect on the ocean waters because water is liquid and can freely move about.
  • The moon’s attraction causes the water of the earth from one region to pile up in on the side nearest the moon, i.e. at A. This being of water at A is an ordinary high tide. ‘
  • At the same time, a counter-bulge occurs on the opposite side of the earth, resulting in a high tide at B. The cause for this high tide is to be found in the ‘centrifugal force’ that is set up by the rotation.
  • Between these areas of high tides are areas o£ lower water at C and D since the moon’s pull draws water from these parts. These are areas of low tides.

Question 3.
Why do the ocean currents flow? How do they affect the climate of any country?
Answer:
Influence of Oceanic Currents :
1. Influence on Temperature. Warm currents raise and cold currents lower the temperature of the coastal regions along which they flow. Labrador coast remains ice-bound for about nine months in a year due to the cold Labrador current.

On the other hand, the temperature of the British Isles remains comparatively high due to the warm Gulf Stream (a warm current in the North Atlantic Ocean),

2. Influence on Rainfall. Winds blowing over warm currents pick up moisture which when condenses causes heavy rains. On the other hand, winds blowing over cold currents get cold and thus do not pick up moisture. Therefore, they do not cause rains. Western Europe receives heavy rainfall due to the warm Gulf Stream. On the other hand, the western coasts of South America, Africa and Australia are washed by the cold currents and therefore, do not get any rain. As a result, big deserts such as Atacama (South America), Sahara, Kalahari and Namib (Africa) and West Australia have 1, formed.

3. Influence on Marine Life. Where a warm and cold current meet together, thick fog is formed. Near Newfoundland the warm Gulf Stream and the cold Labrador current meet together and this results in the formation of very thick fog. As a result, fish gather here in large number and these areas have become the fishing grounds of the world.

4. Influence of Navigation. In pre-steamship days the influence of currents was very important. The ships used to drift with the help of currents. Ships from India used to sail towards Iran and Arabia with the north-east monsoon drift in winter and would return to India with the south-west monsoon drift in summer. In the modern times also, ships prefer to sail with the ocean current as it adds to their speed.

PSEB 7th Class Social Science Solutions Chapter 4 Ocean

Question 4.
Explain with illustration the Atlantic Ocean Currents.
Answer:
There are two fixed circles of Atlantic ocean currents :

  1. North Circle,
  2. South Circle.

1. North Circle:

  • North equatorial current: Because of trading winds, the water of the ocean starts flowing from east to west. It happens in the north of equator. It is a hot water current.
  • Gulf Stream: North equatorial current flows from Africa to America. When this current goes to north-west along the eastern coast of America then it becomes Gulf stream. It starts from Maxico and reaches Newfoundland Islands.
  • The Labrador Current: It is a cold current. It comes from north side and meets the Gulf stream near the Newfoundland Islands.
  • North Oceanic Current: After Newfoundland the Gulf stream takes easterly direction under the effect of western winds.
  • Canery Current: The north oceanic current hits the western coast of Europe and is divided into two parts. Its one part goes to south which is known as Canery current. It is a cold current. In the end this current meets north equatorial current and completes the north circle.

2. South Circle: This circle moves in anti-clockwise direction.

  • South Equatorial Current.: It is a hot water current. Because of the effect of trading winds, the sea current starts flowing from East to West on the south of equator.
  • Brazilian Current: The South Equatorial current hits the Brazilian coast where it is divided into two parts—The part which flows towards south along side Brazilian coast is known as Brazilian Current.
  • Falkland Current: A cold stream from South side meets the Brazilian current and is called Falkland Current. Then this current goes eastways under the effect of western winds.
  • Venezuela Current: Its a cold water stream. It is generated from Faulkland current. It flows towards north alongside the western coast of South Africa.

Question 5.
Explain with illustration the Pacific Ocean Currents.
Answer:
The Pacific Ocean is the biggest and the deepest ocean. Its currents can be divided into two parts :
1. North Circle:
PSEB 7th Class Social Science Solutions Chapter 4 Ocean 6

  • North Equatorial Current: In the northern part of Pacific ocean, there are trading winds which make the currents flow from east to west. This current is known as north equatorial current. It is a hot water current.
  • Kuroshivo Current: The north equatorial current flows towards north when it comes in eastern islands. Here it is called Kuroshivo current.
  • North Atlantic Ocean Current: When Kuroshivo current hits the eastern coast of India then it start flowing towards north east. It is called north Atlantic ocean current.
  • The California Current: The north Atlantic ocean current hits the western coast of North America. Here, it is divided into two parts: One part is called Alaska current and the other is known as California current. Because the California current comes from polar region. So, it is a cold current.

2. South Circle:

  • South Equatorial Current: In the South of equator the sea water starts flowing east to west under the impact of trading winds. It is a hot water current,
  • Eastern Australian Current: It is also a hot water current. When the south equatorial current reaches the eastern island, it takes southward direction and starts moving near the eastern coast of Australia. So it is called eastern Australian current.
  • Pacific Ocean Southern Current: It is again a hot water current. Eastern Australian current takes eastward direction because of the effect of western winds. Because it is in south hemisphere, it bends towards west and is known as pacific ocean southern current.
  • Peru’s Current: It is a cold stream. The Pacific ocean’s southern current hits the western coast of South America and starts flowing from south to north. It is Peru’s current, it meets the equatorial current and completes the circle of Pacific ocean currents.

PSEB 7th Class Social Science Solutions Chapter 4 Ocean

Question 6.
How does the Tide occur? Justify with diagram.
Answer:
The oceanic water twice rises towards the coast and twice comes down towards the sea. This up and down movement is called the tide.
PSEB 7th Class Social Science Solutions Chapter 4 Ocean 7
Reasons For Tide: Tides take place because of the attraction of the sun and moon. The attraction of the sun is many times more than the moon attraction but because the moon is nearer to earth so it creates more effect on the oceanic water i.e. why the moon attraction is considered as the main source of tides.

High Tides: High tide means when the wave in the ocean rises very high, it happens when the sun and moon both pull the ocean water upwards. High tides take place only on high moon days or no moon days. Because on both these days sun, moon and earth are in a straight line, and the waves in the ocean are more than what they normally are.
PSEB 7th Class Social Science Solutions Chapter 4 Ocean 8

Low Tides. On the 7th and 21st day of full moon night both moon and sun make 90° angle with the earth. So both these pull the ocean water towards each other. Because the moon is closer to the earth, the water rises towards the moon, but the opposite power of the sun almost cancels the effect of moon power. So the rise of the sea waves is reduced to a low level. It is called low tides.

Question 7.
What are ocean currents? What are the causes of their origin?
Answer:
That part of seawater that systematically moves from one place to another place in a fixed direction, is known as current. In fact, these are the reverse of hot and cold water flowing inside the sea.

The reasons for currents are as follows:

  • The Winds. Routine winds always flow in the same direction. They make the seawater also flow alongside. Thus the currents take place.
  • The difference in Temperature. The temperature is more in equatorial regions. Because the seawater expands and moves towards the polar region. On the other side, the polar regions have low temperatures and the water there starts moving towards the equator inside the sea. Thus currents are created.
  • The difference in Salinity. There are so many salts mixed in seawater. The water which has more salts it becomes heavy and starts going down the sea. To take its place the water with less salt, which is lighter, starts flowing towards the heavy salt side, so the currents take place.
  • Formation of Continental Coasts. The currents flow along the Continental Coasts. So the formation of continental coasts gives new direction to the currents. With every change of direction, a new current is born.

PSEB 7th Class Social Science Solutions Chapter 3 Atmosphere and Temperature

Punjab State Board PSEB 7th Class Social Science Book Solutions Geography Chapter 3 Atmosphere and Temperature Textbook Exercise Questions and Answers.

PSEB Solutions for Class 7 Social Science Geography Chapter 3 Atmosphere and Temperature

SST Guide for Class 7 PSEB Atmosphere and Temperature Textbook Questions and Answers

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

Question 1.
What do you understand by the atmosphere?
Answer:
There is a big protective balloon around the earth with a radius of almost 1600 kins. But the breatheable air (99%) is in the radius of 32 kms only.

Question 2.
Why we study atmosphere in Geography?
Answer:
Because atmosphere is the factor which mostly affects the life on earth.

Question 3.
Which is called Tropopause limit?
Answer:
The upper limit of stratosphere is known as tropopause limit.

Question 4.
What do you understand by Exosphere?
Answer:
The outer layer of atmosphere is called Exosphere. We don’t know much about this layer. Only this much is known that this layer contains very light gases like Hydrogen and Helium.

PSEB 7th Class Social Science Solutions Chapter 3 Atmosphere and Temperature

Question 5.
What are the elements other than the gases present in the atmosphere?
Answer:
Water vapours and dust particles besides gases which are present in atmosphere.

Question 6.
What is air pollution?
Answer:
Every year, thousand tons of pollutants accumulate in atmosphere. These pollutants are not natural. This man-made activity is called air pollution. It is of two types—Solid and Gas.

Question 7.
What is temperature and what are the units of measuring the temperature?
Answer:
In the air, the current heat element is called its temperature. Like the air temperature, the element of current heat inside something or organism is also called temperature. The temperature remains fluctuating.

Units of measureing temperature are :

  1. Celsius Scale
  2. Fahrenheit Scale.

Question 8.
Why is temperature very high on the Equator?
Answer:
On the equator, the’ sun rays are very -straight, so the temperature is more.

II. Give answers to the following questions in about 50-60 words.

Question 1.
What are the main factors that cause air pollution?
Answer:
1. Solid factors:

  • Volcanoes pollute air through dust particles,
  • In cities, many solid particles are emitted into air by man-made activities.
  • After fuel combustion, the carbon particles accumulate in the air.
  • The factories emit dust pollutants which contains Asbestos—a dangerous source of pollution.

2. Gaseous factors:

  • The fumes emitted by motor vehicles is a dangerous source of air pollution.
  • There is an extremely poisonous gas called carbon monoxide in the atmosphere where there is a maximum of transportation vehicles.
  • Smog is another air pollutant that is a combination of smoke and fog.
  • Another main reason for air pollution is the less ozone in the air.

Question 2.
What we call the lower layer of the atmosphere?
Answer:
The lower layer is called troposphere. This is the most dense layer of the atmosphere. It is actually an oval-shaped construction around the earth. Its average height is 12 kms. On the equator, it is almost 16-18 kms in height while at the poles, it is almost 6-8 kms. This layer always remains disturbed because all the activities like rainfall, clouds, thunder storms, etc. take place in this layer only. Most of the water vapours are also found in troposphere. 75% of air is found in the troposphere. When we move up the troposphere, the temperature decreases and the rate of decrease is 6.5 Celsius per km.

PSEB 7th Class Social Science Solutions Chapter 3 Atmosphere and Temperature

Question 3.
Write the ratio of main gases in the air.
Answer:
Air is actually a mixture of gases. Main gases are Nitrogen and Oxygen. Other important gases are argon, Carbon dioxide and Hydrogen. Nitrogen is almost 78.03%, Oxygen is 20.99%, Argon is 0.94%, Carbon dioxide is 0.03% and Hydrogen is almost 0.01%. In the whole atmosphere, more or less the quantity of gases almost remains stable. But as the height increases, the percentage of these gases decreases.

Question 4.
In which layer of the atmosphere the ozone gas exists? Why is it so important?
Answer:
In the atmosphere, ozone gas is found in stratosphere.

Importance It is a very important gas because it protects the live-world from the dangerous ultraviolet rays of the sun. It absorbs the heat from sun and the heat remains in the stratosphere. The upper layer of stratosphere remains heated as a consequence.

III. Fill in the Blanks :

Question 1.
As we go up to the hills, the temperature ___________
Answer:
decreases

Question 2.
The main sources of the temperature are ___________ and ___________
Answer:
sun, internal parts of earth

Question 3.
The ozone gas absorbs ___________ rays.
Answer:
ultraviolet

PSEB 7th Class Social Science Solutions Chapter 3 Atmosphere and Temperature

Question 4.
The electrically charged particles are found in ___________ layer.
Answer:
ionosphere

Question 5.
The wireless communication system works under ___________ waves.
Answer:
radio

Question 6.
___________ gas is found in maximum quantity in atmosphere.
Answer:
Nitrogen.

IV. Things to do:

Question 1.
What rules should be followed to avoid air pollution, prepare a chart and put it in your classroom.
Answer:
Do it yourself.

Question 2.
Draw a diagram of atmosphere showing different layers.
Answer:
Do it yourself.

PSEB 7th Class Social Science Guide Atmosphere and Temperature Important Questions and Answers

Multiple Choice Questions :

Question 1.
Trade winds are called :
(a) Seasonal winds
(b) Permanent Winds
(c) Local Winds
(d) Western Winds.
Answer:
(b) Permanent Winds.

PSEB 7th Class Social Science Solutions Chapter 3 Atmosphere and Temperature

Question 2.
The most important layer of the atmosphere is :
(a) Troposphere
(b) Tropospause
(c) Stratosphere
(d) Stratopause.
Answer:
(a) Troposphere.

Question 3.
How much percentage of atmosphere is made up of oxygen gas?
(a) 10.95%
(b) 20.95%
(c) 25.95%
(d) 30.55%.
Answer:
(6) 20.95%.

Question 4.
Which is the closest layer to the earth?
(a) Stratosphere
(b) Troposphere
(c) Mesosphere
(d) Excosphere.
Answer:
(b) Troposphere.

Question 5.
Which winds are seasonal winds?
(a) Trade
(b) Permanent
(c) Monsoons
(d) Westerlies.
Answer:
(c) Monsoons.

Fill in the Blanks :

Question 1.
Atmosphere is a mixture of different ___________
Answer:
Gases

PSEB 7th Class Social Science Solutions Chapter 3 Atmosphere and Temperature

Question 2.
Nitrogen and ___________ are the two main gases of atmosphere.
Answer:
Oxygen

Question 3.
___________ layer is the closest to the earth.
Answer:
Troposphere

Question 4.
The uppermost layer of stratosphere is called ___________
Answer:
Tropopause

Question 5.
___________ is the unit of measuring the temperature.
Answer:
Farenheit Scale.

True / False :

Question 1.
The big protective layer surrounding the earth is called lithosphere.
Answer:
False

Question 2.
On the equator temperature is very high.
Answer:
True

PSEB 7th Class Social Science Solutions Chapter 3 Atmosphere and Temperature

Question 3.
Troposphere is the upper most layer of the atmosphere.
Answer:
False

Question 4.
Weather is the day to day phenomena.
Answer:
True

Question 5.
During day time earth’s surface attracts sun rays.
Answer:
True

Very Short Answer Type Questions

Question 1.
Write the elements of Atmosphere.
Answer:
Air, temperature, humidity, air pressure, etc.

Question 2.
What is temperature?
Answer:
In the air, the current heat element is called its temperature. Like the air temperature, the. element of current heat inside something or organism is also called temperature. The temperature remains fluctuating.

PSEB 7th Class Social Science Solutions Chapter 3 Atmosphere and Temperature

Question 3.
Write the importance of the following gases.
Answer:

  1. Nitrogen: It is found in the lower layer of the atmosphere. This gas helps the flora from dying.
  2. Oxygen: It protects the flora and fauna which cannot survive without oxygen.
  3. Carbon dioxide: Carbon dioxide protects the flora. It makes a blanket around the earth and does not let the heat escape from the atmosphere.

Question 4.
What is the importance of water vapours?
Answer:
The water vapours play a great role in changing the temperature.

Question 5.
What is condensation?
Answer:
When the air heats up it expands and becomes lighter and goes up in the air. The heavy air comes down and takes the base of displaced air. This process goes on and takes the form of a cycle. This cycle is known as condensation process.

Question 6.
As we move up the mountains, the temperature decreases. Why?
Answer:
The reason for less temperature at high places is that rays from the sun first heat up the surface and then heat up the atmosphere. So, the atmosphere near the earth’s surface becomes hot quickly and the upper part becomes less hot. This is the reason when we go up the mountains the temperature decreases.

Question 7.
(a) Write a note on ozone layer of the atmosphere.
Answer:
Ozone layer: A thick layer of ozone gas exists in upper atmosphere. This layer is useful as it absorbs ultraviolet rays of the sun.

(b) Why is it depleting? Where has been a hole in this layer found?
Answer:
ue to excessive use of chemicals and carbons (which react with ozone layer) the ozone layer is being depleted. This atoms explosions also deplete the ozone layer. In 1980, a hole in the ozone layer was noticed over Antarctica,

(c) What are its harmful effects?
Answer:
Through this hole, ultra-violet rays will reach the earth. These rays are harmful as these cause skin cancer. It may cause blindness.

PSEB 7th Class Social Science Solutions Chapter 3 Atmosphere and Temperature

Question 8.
“The atmosphere acts as a blanket or a glass-house.’ Discuss.
Answer:
Atmosphere acts like a blanket keeping the earth warm. It absorbs incoming solar radiation and does not allow radiation to escape. So equable temperatures are found.

Question 9.
Name the layers of atmosphere.
Answer:

  1. Troposphere
  2. Stratosphere
  3. Mesosphere
  4. Thermo-sphere.

Question 10.
Why there is difference in day time and night time temperature?
Answer:
During day time, earth’s surface attracts sun rays and at night, releases the heat absorbed. So at night, the temperature is low as compared to the day.

Short Answer Type Questions

Question 1.
Explain the Greenhouse effect of the atmosphere.
Answer:
The atmosphere is heated by the radiation from the earthy surface flow. This action is compared to that of a glass house on greenhouse in which vegetables and flowers are grown in polar areas. Glasshouse permits radiations to get in but does not allow radiation to escape out. Therefore glass house is warmer from inside than outside. The atmosphere also acts like a blanket keeping the earth warm. It is known as the greenhouse effect of atmosphere. This is due to presence of carbon dioxide in the atmosphere. Carbon dioxide has the ability to absorb earth radiation. The carbon dioxide layer acts as a glass roof of the greenhouse. With the increase in carbon dioxide, the temperature of the earth is increasing. Due to this, the year 1955 was the hottest year in India during this century.

Question 2.
What is global warming? What are its causes? State its effects.
Answer:
Global warming. The burning of fossil fuels (coal, gas, petroleum), the cultivation of soil, large scale industrialisation, rapid means of transport and deforestation has caused an imbalance in the atmosphere. These activities are increasing the amount of carbon dioxide. Thus greenhouse effect has raised the average, the temperature of the earth by 0.5° C. By the year 2050, the earth’s average temperature will go up by 2°C. This is called global warming. Global warming is causing a rise in sea levels due to melting of glaciers. It is threatening to submerge many coastal areas.

PSEB 7th Class Social Science Solutions Chapter 3 Atmosphere and Temperature

Question 3.
Write a note on Environmental pollution.
Answer:
Environmental pollution has become a serious problem for mankind. It is threatening the existence of mankind. The composition of air is being altered by undesirable chemical, physical and biological elements. It is known as air-pollution.

Pollutants: The common pollutants found in air are as follows :

  • Deposited matter like soot, smoke, sand-dust.
  • Gases like sulphur, carbon monoxide, nitrogen oxide, Ammonia, Flourine, etc.
  • Chemical Compounds like arines, phosgenes, detergents.
  • Metals like lead, iron, zinc, mercury.
  • Sewage.
  • Radio-active substances.
  • Noise and heat.

A. Atmospheric Pollution: Atmosphere is of fundamental importance for our existence. Due to industrial revolution, the atmospheric pollution is increasing gradually. It has harmed the ultra-violet shielding ozone layer. The addition of heat-trapping greenhouse gases will cause a disaster.

The volcanic eruptions, forest fires, natural decay of organic and inorganic matter is causing visibility. Smoke is injurious to health. Acid rain has changed the composition of air and water.

Fossil Fules: The buring of fuels and chemicals is increasing the amount of carbon dioxide in atmosphere. It has increased by 25%. With the result, the average temperature of the earth is increasing. It has increased 0.3°C to 0.7°C during the last century. Deforestation has also led to increase in carbon-dioxide. The increasing use of fuels in vehicles has increased the amount of sulphur dioxide, carbon monoxide and has created many respiratory diseases.

B. Water Pollution: Water is another indispensable source of our life. Pollution of water has caused far-reaching implications. It is a serious problem in metropolitans like Delhi, Kolkata and Mumbai. It not only affects the water of rivers, tanks and lakes; but also ocean water.

The following factors affect water pollution

  • Domestic sewage .
  • Industrial wastes
  • Agricultural activities
  • Thermal pollution
  • Marine pollution.

C. Land Pollution: Land is one of the most important components of life support system. Land is degrading due to overuse from centuries depletion of land is caused by :

  1. Soil erosion
  2. Pollutant.

PSEB 7th Class Social Science Solutions Chapter 3 Atmosphere and Temperature

Question 4.
Explain in detail the layers of atmosphere.
Answer:
It is estimated that the atmosphere is spread up to a radius of 1600 kms. It can be divided into four main layers described as follows :
1. Troposphere: This is the lowermost layer of atmosphere and is closest to the earth. Its average height is 12 km. Most of the clouds, water vapours and dust particles are found in this layer. This is the weather-making layer and favours human life. The temperature decreases in this layer at the rate of 1°C for every 165 metres.

2. Stratosphere: This layer lies next to the troposphere. Its height ranges from 12 to 80 km. The temperatures are very low and fairly constant. It is free from clouds, dust particles and convection currents.

3. Ozonosphere: This is a zone of ozone gas. It absorbs ultraviolet rays of the sun. It has high temperature. It is known as thermosphere also.

4. Ionosphere: This layer extends upto a height of 800 kms. Ozone gas, lone gas electrons and atoms are found in this layer. This layer absorbs ultraviolet rays of the sun and reflects radio waves.

5. Exosphere: This is the uppermost layer of the atmosphere. Its upper height is unknown due to inaccessibility. It is a highly rarefied layer. It is known only to aerospace-ships.

Long Answer Type Questions

Question 1.
Explain the composition of atmosphere.
Answer:
Composition of the Atmosphere. The atmosphere mainly consists of a mixture of gases in a fairly constant composition.

The atmosphere is composed of the following three elements :
1. Gases: Nitrogen and Oxygen are the two major gases found in the atmosphere. In pure dry air, Nitrogen occupies 78% and Oxygen occupies 21% by volume. The remaining 1% is composed of a number of gases like Hydrogen, Argon, Ozone, Helium, Carbon dioxide. The proportions of the gases remain constant.

Active gases: Oxygen, Nitrogen, Hydrogen, Carbon dioxide, Ozone are active gases. Oxygen is the most vital gas for sustaining life. Nitrogen and Carbon dioxide are essential for plant life and help in the process of Photosynthesis.
Inert Gases: Argon, Neon, Helium, Krypton are inert gases which are not so effective.
PSEB 7th Class Social Science Solutions Chapter 3 Atmosphere and Temperature 1
Atmosphere: Composition

Gas % of total Atmosphere Height in km.
Nitrogen 78.03% 125
Oxygen 20.95% 95
Argon 0.93%
Carbon dioxide 0.03% 30
Hydrogen 0.01% 200
Other gases 0.05%
Total 100.00%

It shows that Nitrogen (N2) alone occupies about four-fifths of air by volume and oxygen (02) one-fifth. In addition to the above, other gases like Neon, Methane, Krypton and Radon are also present in the atmosphere. The atmoshpere is odourless, colourless and tasteless. It is mobile, elastic, both compressible and expandable. It is invisible but, it has weight and pressure.

2. Water Vapour: Water vapour represents 2% of the air by volume. It is mostly found in the lower layers of the troposphere. About half the water vapour in the air lies below an altitude of 2000 metres. It is of primary importance to man. It absorbs insolation. It is the source of all condensation and precipitation on the earth. Water vapour, an unstable element is obtained from oceans, lakes, rivers and other water bodies.

3. Dust Particles: The atmosphere holds in suspension many dust particles whose sizes vary. The major source of dust particles are deserts, lake beds, beaches and dry river beds. These are found in the lower layer of the atmosphere. These affect sun rays by scattering and absorbing insolation. These are responsible for the formation of clouds, fog and smog. Solid particles like carbon, salt, pollen grains, etc. are also found in the lower layers of the atmosphere.

PSEB 7th Class Social Science Solutions Chapter 3 Atmosphere and Temperature

Question 2.
Explain in detail the factors affecting the temperature of a place.
Answer:
Temperature is never stable. It goes on changing with time and place. Many factors affect the temperature which are as follows :
1. Distance from the Equator: On the equator the sun rays are straight. So, the heat is more and as a result the temperature is more. As we move towards polar regions the sun rays become .slant and as a result these regions are cold and the temperature is very less.

2. Height from Sea Level: The place which is higher than the sea level has less temperature. The reason is that when we near the sea coast the air is dense but as we move up the air becomes thin. So, the high places have low temperature, e.g. Shimla is at a more height than Chandigarh. So, the temperature of Shimla is less than the temperature of Chandigarh.

3. Distance from Sea: In comparison to land, the water beats up early. So, the places which are near the sea the temperature is neither more nor less. But the places which are away from the sea, there the temperature is less in winter and more in summer, e.g. Mumbai has stable temperature because of its closeness to sea. Whereas, Amritsar is very far away from sea and as a result there is much difference in summer and winter temperature.

4. Sea Waves: The sea waves are of two types hot and cold. Where the hot waves flow the temperature there increases and where the cold waves flow the temperature there decreases.

5. Winds: The winds that come from sea are full of water vapours and produce rainfall. As a result the temperature becomes less. On the other hand the winds coming from dry areas increase the temperature of places which come in their contact.

6. Direction of Mountains: The mountains which are horizontal to the direction of winds they cannot stop the watery winds and as a result no rainfall happens there. But the areas with vertical mountains to the wind direction can stop the winds and cause rainfall.

7. Slope of Mountains: The mountain’s slope facing the sun had more temperature. While the other side of the mountains has no temperature.

8. Types of Soil: The sandy soil heats up quicker than the clay. So, in the arid areas the temperature in the daytime, is more. But in the nighttime, it is less.

9. Clouds and Rains: The places where there are more clouds and rains have less temperature because clouds stop the sunlight from reaching the earth directly. As a result, the temperature is less. Similarly, the rains also decrease the temperature.
PSEB 7th Class Social Science Solutions Chapter 3 Atmosphere and Temperature 2
Layers of Atmosphere

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Punjab State Board PSEB 7th Class Social Science Book Solutions Geography Chapter 2 The Internal and External Face of the Earth Textbook Exercise Questions and Answers.

PSEB 7th Class Social Science Solutions Geography Chapter 2 The Internal and External Face of the Earth

SST Guide for Class 7 PSEB The Internal and External Face of the Earth Textbook Questions and Answers

I. Give answers to the following questions approximately in 1-15 words.

Question 1.
How many shells of the earth are there? Name them.
Answer:
Lithosphere, Mantle and Core. These are called Sial, Sima and Nife in that order.

Question 2.
How many types of Rocks are found on the earth?
Answer:
Igneous rocks, Sedimentary rocks, Metamorphic rocks.

Question 3.
Write down about the Mantle part of the Earth.
Answer:
Below the earth’s crust is Mantle. Its normal thickness is 2900 kms deep down to earth’s interior.

Question 4.
By which name the inner most part of the earth is called? What are the components of this part?
Answer:
The core of the earth is called ‘Nife’. It is made up of Nikel and Iron (Ferrous).

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 5.
How can we avoid soil erosion?
Answer:

  • By planting more and more trees.
  • By adopting developed means of agriculture.
  • By decreasing the grazing area of cattle.

II. Give answers to the following questions approximately in 50-60 words.

Question 1.
What are igneous rocks? How many types are there of these rocks? Write about the Intrusive rocks.
Answer:
Igneous shell is the shell which is made up by cooling of Magma and Lava. These rocks are of two types: Intrusive/Extrusive.
Sometimes Magma get cold and slowly solidifies inside the earth’s surface, these are called Intrusive Igneous Rocks. While sometimes Magma gets cold and solidifies near the earth’s surface then these rocks are called Extrusive Igneous Rocks.

Question 2.
What are the sedimentary rocks? How many types are there of these rocks?
Answer:

  1. They are called secondary rocks.
  2. They form from deposits or sediments obtained from weathering and erosion of other rocks.
  3. They contain fossils.
  4. They are always layered.
  5. Sandstone, shale, gravel and conglomerate are examples of these rocks.
  6. On the basis of construction, layered rocks are of two types:
    (i) Fossil layered rocks.
    (ii) Non-fossil layered rocks.

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth 1

Question 3.
Write about Metamorphic rocks, give specific example of these rocks.
Answer:
Metamorphic Rocks: These rocks are formed by ‘metamorphism’ or change of form of igneous and sedimentary rocks. The change takes place in hardness, colour, texture and composition of minerals in rocks deep inside the earth due to pressure and temperature. Thus original igneous rock like mica may be changed to schist, granite to gneiss and sedimentary rocks like limestone to marble, sandstone to quartzite and peat to coal.

Characteristics:

  • They are very hard.
  • They contain useful materials and minerals like building materials, marbles, gems, rubies and sapphires. Taj Mahal is made of white marble.

Question 4.
What kind of mineral is mica, for what purpose is it used?
Answer:
Mica is a non-metallie mineral: It has a great importance. This mineral is very useful in manufacturing eletromic goods. It is also used in making other things like lamps, chimneys, paints, radars, rubber, poper, transparent sheets and aeroplanes.

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 5.
Which material is called as ‘Liquid Gold’? Give brief introduction.
Answer:
Mineral oil is known as Liquid Gold. This name has been given because of its increasing use and importance. It, is also called Petroleum or driving energy. It is also extracted from earth like other minerals. It is made up of two words- Petra and Oliuin. In Latin language Petra means rock and Olium means oil i.e. oil received from rocks. It is a fossil fuel which is made up of animals leftovers being pressed inside Sedimentary rocks.

Question 6.
Write down the importance of the soil on the earth.
Answer:
Soil is a valuable natural resource. Its importance is in its fertility. Many human and economic activities depend upon soil. Most of the civilizations have flourished near the fertile soil beds of Nile and Indus rivers, Tigris, Euphrates and Yangste valleys. Even today fertile valleys and rivers attract dense population. India has been able to produce foodgrains for its large population on the strength of its fertile soil.

III. Write the answers to the following questions approximately in 125-130 words.

Question 1.
Write in detail about the rocks available on the earth.
Answer:
On the basis of their formation rocks are of three chief types as shown in the diagram, namely— Igneous, Sedimentary and Metamorphic.
PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth 2

1. Igneous: These rocks are formed from cooling and solidification of molten material rising from interior of the earth called magma. When cooling and solidification happens just near the ground or above the ground they are called Extrusive Igneous Rocks. If cooling and solidification happens inside the earth, these rocks are called Instrusive Igneous Rocks. Basalt and Rhyolite are examples of extrusive igneous rocks and granite and gabro are examples of intrusive igneous rocks.

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth 3
Igneous Rocks

Characteristics:

  • When igneous rocks are exposed on the surface of the earth they are weathered and provide materials for other types of rocks. As a result the igneous rocks are called Primary Rocks.
  • These rocks contain crystals whose size depends on rate of cooling.

2. Sedimentary Rocks: The material for sedimentary rocks may be derived from weathering and erosion of all types of rocks- igneous, metamorphic or old sedimentary rocks. They may contain fossils formed from remains of dead plants and animals.

There are two types of sedimentary rocks: inorganic and organic,
(a) Organic Sedimentary rocks are formed from organic matter derived from plant and animal remains, shell and skeletons of dead marine animals, decayed and decomposed plant and animal life as well as direct precipitation of minerals in solution of water.
(b) Inorganic Sedimentary rocks are formed due to weathering and erosion of all types of old rocks, clay, sand and mud deposited in oceans and lakes.

Characteristics:

  • They have a layering arrangement.
  • They may contain fossils.
  • They may have ripple marks left by water.
  • They are softer than any other rock.
  • They are pervious or water can easily enter.
  • There are no crystals in sedimentary rocks.
  • Secondary ores of bauxite, manganese and other minerals are found in secondary rocks. Only sedimentary rocks are sources of fossil fuels. They also provide rich soils and materials for building and construction industry.

3. Metamorphic Rocks: Igneous and sedimentary when subjected to pressure and heat form sedimentary rocks. Examples- sandstone, granite, gnesis. Metamorphic rocks are made up by two ways and are found deep inside the surface of the earth.

The two ways are:

  1. Transformation by heat. It happens because of hot magma, which solidifies the rocks that comes into its contact.
  2. Transformation by pressure. Sometimes the pressure of upper rocks transforms the structure of lower rocks.

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 2.
What are minerals? Which minerals are available on the earth? Classify them and write about the metallic minerals.
Answer:
The substances that create rocks are known as minerals. These are extracted through mining. The classification is”as follows :

  1. Metallic minerals: It contains the particles of metals. It includes iron, copper, tin, aluminium, gold, silver, etc.
  2. Non-metallic minerals: These don’t contain the particles of metals. These are sulphur, gypsum, abhrak, phosphorus, potassium, etc.
  3. Power minerals: These minerals give us energy, which helps us to run our factories and motor vehicles. Coal, petroleum, natural gas are main power minerals.

Metallic minerals :
1. Iron: The iron ore is used from a small nail to a very big ship. The whole industrial machinery, motor vehicles, rails, agriculture machinery all are based on iron ore. The iron and steel has brought revolution in the industrial sector. In India it is produced mainly in Orissa, Jharkhand, Bihar, Madhya Pradesh, Chhattisgarh, Karnataka and Goa.

2. Copper: Copper is the earliest found metal in the human history. From the industrial point of view, after iron comes the place of copper. The metallic age started with the use of copper. Many utensils are made of copper. In today’s age its importance has increased. It is a good conductor of electricity so, it is used for making electric cables. Telephone cables, railway engines, aeroplane and watches, etc. contain the use of copper. Chile, in South America, is the biggest producer of copper in the world followed by USA. In African continent there are maximum stores of copper. India, Japan, Australia also produces copper. In India, Jharkhand, Madhya Pradesh, Rajasthan are known for copper.

3. Bauxite: It is derived from aluminium. It is a light metal and is used in making aeroplanes. Moreover trains, motor vehicles, buses and electric cables also contain bauxite. The products made up of this metal do not get rusty. So, these products can be used for fairly long time.

Maximum bauxite is available in Australia. In India it is found in Maharashtra, Madhya Pradesh, Chhattisgarh, Jharkhand.

Question 3.
What are mineral fuels? Give details of any mineral fuel.
Answer:
These minerals give us energy and required ignition run factories and motor vehicles. Main power minerals are coal, mineral oil and natural gas.

Out of this coal and mineral oil have special importance the description is as follow :
1. Coal: Coal is the main power mineral. These days the use of coal has decreased. Now it is used in thermal plants for producing electricity. The coal used for this purpose is stone coal. This coal was made in the sedimentary rocks deep inside the earth. It took crores of years in this process. Most of the coal stock in the world is found in 35° to 65° latitude. 90% of world coal is found in China, USA, Russia and European countries. Besides there are large stocks of coal in South America, Africa, North America and Asian sub-continent. Japan and Thailand also have stock of coal.

India produces 5% of coal. Damodar Valley is the main coal-production belt. Madhya Pradesh and West Bengal are coal-rich states.

2. Mineral Oil: It is known as Liquid Gold. Its name has been given because of its use and importance. Its called petroleum or driving force. Because it is extracted from earth like other minerals so it is called mineral oil. It is given the name of petroleum because it is made up of two words— Petra+Olium. Petra stands for rocks and olium means oil. So the literal meaning of Petroleum is oil received from rocks. It is fossil fuel. Most of the Petroleum that we get from inside the earth is in raw form. After refinement of thfs unrefined raw form, we get many products like Petrol, diesel, kerosene oil, gas, grease, wax, etc.

Most of the oil stock in the world is in South-west Asia, which includes areas like Saudi Arab, Iran, Iraq, Kuwait and United Arab Emirates.

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 4.
Write in detail about the soils available in India.
Answer:
Soil is an important resource that becomes the basis of agriculture and foodgrains production. In India, six types of soils are found of which the following four types are major :

  1. Alluvial soil
  2. Black soil
  3. Red soil
  4. Laterite soil.

1. Alluvial Soil: This soil is derived from sediments of rivers and is confined to river basins and coastal plains. Alluvium is very fertile because it is renewed every year during floods or deposition work of rivers. It contributes enormously to growth and development of agriculture in India. It is found in the states of Punjab, Haryana, Uttar Pradesh, Bihar, Orissa, Bengal, Rajasthan and coastal areas of Brahmaputra valley and Peninsular India.

2. Black Soil: This lava soil is also known as Regur soil or Black Cotton soil. It is black because it is formed in its place of origin. It is found in parts of Gujarat, Madhya Pradesh, North Karnataka, Southern Tamil Nadu and parts of Madhya Pradesh.

3. Red Soil: The presence of iron oxide is responsible for reddish colour. When fertilisers are added these soil become very productive for growing crops like rice, millets, cotton and sugarcane. Red soils are found in Malwa region, Chhotanagpur plateau, parts of Chhattisgarh, Tamil Nadu, Karnataka, Andhra Pradesh and Orissa.
PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth 4

4. Laterite Soils. These are not very fertile soils. They occur in high places of plateau region where rainfall leaches nutrients in the soil. Laterite rock is best suited for building purposes rather than for agriculture. These soils are found in parts of Tamil Nadu, Karnataka, Andhra Pradesh. Orissa, Bengal and Summits of Western and Eastern Ghats.

IV. Activities:

Question 1.
Make a model of the earth showing its layers.
Answer:
Do it yourself.

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 2.
Is soil erosion a serious problem? Discuss it in your class.
Answer:
Soil erosion is a global problem. Deforestauon, overgrazing bv animals are the main causes. The rate of soil erosion in India is the highest. It takes a long time to form fertile soils, but in a short time soil erosion removes the soil.

PSEB 7th Class Social Science Guide The Internal and External Face of the Earth Important Questions and Answers

I. Multiple Choice Questions :

Question 1.
The rock which is made up of molten magma is :
(a) Igneous
(b) Sedimentary
(c) Metamorphic
(d) Sedentary.
Answer:
(a) Igneous.

Question 2.
Which of the following is an example of sedimentary rocks?
(a) Basalt
(b) Granite
(c) Gabro
(d) Sandstone.
Answer:
(d) Sandstone.

Question 3.
Deccan plateau is made up of :
(a) Basalt
(b) Gabro
(c) Slate
(d) Granite.
Answer:
(a) Basalt.

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 4.
Where is the deepest mine found on earth?
(a) In South Africa
(b) In North Africa
(c) In South America
(d) In Australia.
Answer:
(a) In South Africa.

Question 5.
Laterite soils are found :
(a) Karnataka
(b) Punjab
(c) U.P.
(d) Bihar.
Answer:
(a) Karnataka.

Fill in the Blanks :

Question 1.
__________ is a dark substance formed in soils.
Answer:
Humus

Question 2.
__________ rocks have more sand.
Answer:
Porous

Question 3.
Limestone is changed into __________ under great heat and pressure of the above layers of the rocks.
Answer:
Marble

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 4.
When magma reaches earth surface, it is called __________
Answer:
Lava

Question 5.
Sedimentary rocks are called __________ rocks .
Answer:
Secondary.

True / False :

Question 1.
The innermost layer of the earth is called core.
Answer:
True

Question 2.
The combined form of natural minerals is called rocks.
Answer:
True

Question 3.
Sial made up of Silica and Alumina.
Answer:
False

Question 4.
Sulphur, Gypsum are non-metallic minerals.
Answer:
True

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 5.
Coal, Petrol, Natural gas etc. are considered power resources.
Answer:
True.

Very Short Answer Type Questions

Question 1.
How is volcanic mountain formed? Give an example.
Answer:
In the lower layers of earth, there is so much heat which results in cuts on earth’s surface, and the hot substance from deep inside earth comes out in the form of . ‘Lava’. When after cooling and solidifying, this lava takes the shape of a mountain then it is called a volcanic mountain. The example is Fugeyama volcanic mountain of Japan.

Question 2.
What is the difference between Porous and Non-porous rocks?
Answer:
Porous rocks have more sand while Non-porous rocks have more of soil in these.

Question 3.
Classify rocks on the basis of absorption.
Answer:
Two types of Rocks: Absorbing and Non-absorbing. While Absorbing rocks easily soak water but non-absorbing rocks don’t easily absorb water.

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 4.
Name two classifications of rocks on the basis of chemical structure.
Answer:

  1. Acidic Rocks
  2. Base Rocks.

Question 5.
What is difference between Lava and Magma?
Answer:
Inside the earth’s surface: Molten substance is called Magma. When it comes outside through pores/cutting in earth’s surface, it is called Lava.

Question 6.
What do you mean by primary rocks? Write their features.
Answer:
Igneous rocks are formed by the solidification of lava. Lava cools rapidly and solidifies on the surface of earth. Crystals are formed due to the cooling of lava. These rocks are intrusive as well as extrusive. It is believed that the earth was in a molten state in the beginning. Igneous rocks were the first rocks to be formed due to cooling and solidification of molten matter. Hence, these are called Primary rocks.

The importance of Igneous rocks
Igneous rocks supply different types of minerals. Granite is used for house-building and idol-making. Basalt is used for road-making. Monuments are made from these hard rocks.

Question 7.
What are the factors on which the qualities of metamorphatic rocks depend?
Answer:
The quality depends on the base rocks i.e. if the metamorphatic rocks are made up of igneous rocks then their qualities are like igneous rocks, and if these are made up of sedimentary rocks then these are like sedimentary rocks.

Question 8.
What is soil?
Answer:
The uppermost layer of the earth’s crust is called soil. It consists of a thin layer of loose material of rock waste. The soil consists of mineral particles, organic matter (humus), water, air and living organisms (bacteria).

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 9.
What are the two elements in soil?
Answer:
The soil has two elements minerals and excreta. The soil contains minerals in good quality and these are derived from basic rocks. The excreta comes from the dead animals. It increase the fertility of soil.

Question 10.
Which soil is known as cotton soil?
Answer:
Black soil is known as cotton soil. It is ideal for cotton agriculture.

Question 11.
Name the types of soils found in India.
Answer:
Alluvial soil, black soil, red soil, laterite soil, dry soil, mountain soil.

Question 12.
Write two features of Alluvial soil.
Answer:

  1. This soil contains potassium, phosphoric acid and lime.
  2. It contains less of nitrogen and bio substance.

Question 13.
Write two features of black soil.
Answer:

  1. It is made up of the flow of lava.
  2. It is useful for cotton agriculture.

Question 14.
Write the names of places in India where black soil is found.
Answer:
It is found in the deccan pleateu as well as Maharashtra, Sourastra, Malwa and Southern Madhya Pradesh Plateau.

Question 15.
Write two features of Laterite soil.
Answer:

  1. Laterite soil is less fertile.
  2. It is only useful for grass and bushes.

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 16.
How can the acid soil be made useful for agriculture?
Answer:
By putting together the irrigation facilities.

Question 17.
What is meant by tectonic plate movements?
Answer:
The earth’s interior is very dynamic. The lithosphere is broken into seven very large and several small plates. This deformation in the earth’s crust and structures produced by this deformation are called tectonics. This model or theory that explains this distribution, evolution and causes of earth’s crustal features is known as the theory of plate tectonics.

Question 18.
What are kqown as rocks? Name the rock-forming materials.
Answer:
Bocks are the chief materials of earth’s crust. Rock-forming materials are known as minerals.

Question 19.
How can we identify mineral which form the rocks?
Answer:
We can identify minerals in rocks by their colour, texture, lustre and hardness. Some minerals like salt can also be identified by tasting but it is not a good method. It can endanger human life.

Question 20.
Name the three groups of rocks on the basis of their formation.
Answer:
The three groups of rocks on the basis’ of their formation are igneous, sedimentary and metamorphic.

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 21.
Why are the Igneous rocks called Primary Rocks?
Answer:
It is believed that the earth was in a molten state in the beginning.’Igneous rocks were the first rocks to be formed due to cooling and solidification of molten matter. Hence, these are called Primary rocks.

Question 22.
Why are fossils preserved in Sedimentary and not in Igneous, rocks?
Answer:
Fossils are remains of vegetation and animals buried under the sediments. The sedimentary rocks are stratified rocks and are found in layers. These fossils are preserved in between these layers. But in Igneous rocks, the fossils are destroyed due to high temperature of lava.

Question 23.
What part do rocks play in Geography?
Answer:
Rocks influence different types of landforms. Different types of minerals are found in rocks. Rocks are used for building purposes. Rocks are the basis of soil formation.

Question 24
How are Igneous rocks formed?
Answer:
Igneous rocks are formed by the solidification of lava. Lava cools rapidly and solidifies on the surface of earth. Crystals are formed due to the cooling of lava. These rocks are intrusive as well as extrusive.

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 25.
What is the importance of Igneous rocks?
Answer:
Igneous rocks supply different types of minerals. Granite is used for house-building and idol-making. Basalt is used for road-making. Monuments are made from these hard rocks.

Question 26.
What do you mean by ‘Deccan trap’?
Answer:
Deccan trap is an extensive area in the N.W. part of India covering about 5 lakh sq. km. It has been formed by lava flows. Lava has solidified to form Basalt. It is useful for cotton cultivation.

Question 27.
Why are sedimentary rocks classfied as belonging to secondary group? How are these rocks formed?
Answer:
The secondary rocks are those which are derived from other rocks. The sedimentary rocks are formed from weathering and erosion of igneous, metamorphic and even other sedimentary rocks.

Question 28.
What are known as fossils? In which types of rocks can fossils be found?
Answer:
Fossils are the remains of dead plants and animals trapped in rocks. They are found in sedimentary type of rocks.

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 29.
Why the ‘Sial’ layer is known by this name?
Answer:
Sial has more of Silicon and Aluminium, That is why it is called Sial (Si+Al).

Short Answer Type Questions

Question 1.
What is humus? How is it formed? What is its significance in soil formation?
Answer:
Humus. Humus is a dark substance formed in soils. It is a dead organic matter formed by decay of animals and plants. Trees, shrubs, grass and bacteria help in the formation of humus. In warmer climates, humus is destroyed by countless bacteria. In colder areas soils are rich in humus and it is collected in the soil. Tropical humid soils are poor in humus because it is consumed by bacteria.

Humus is vital to the fertility of soils. It provides nitrogen, phosphorus and calcium to the soils. It sustains other forms of life. It helps the weathering of minerals to add to fertility of soils. It increases water holding capacity of soils.

Question 2.
What is a bad land topography?
Answer:
A highly dissected land surface is known as bad larid. In sloping areas, gully erosion results in soil erosion. These gullies develop a ravine land a bad land topography. This topography consists of ridges, earth pillars, ravines, escarpments, etc. This topography is found in Chambal Valley of Madhya Pradesh in India.

Question 3.
What is soil-erosion?
Answer:
Soil-erosion. It is the destruction and removal of top soil by running water, wind, etc. So erosion has become a serious problem in many areas Soil formation is a slow process and takes thousands of years to develop, but it may be removed in the matter of a few years.

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 4.
What is soil erosion? Name its types.
Answer:
Soil erosion. Soil erosion is the destruction and removal of top soil by running water, wind, etc. Soil formation is a slow process and takes thousands of years to develop soil; but it may be removed in a matter of few years.

Types of Soil Erosion :
Soil erosion is of three types :

  1. Sheet erosion: When the surface soil is washed away by rain or blown away by the wind.
  2. Gully erosion: When torrential rain forms deep gullies on sloping land.
  3. Wind erosion: When strong winds blow away fine soil in arid areas.

Question 5.
What are the causes of soil erosion?
Answer:
Causes of Soil Erosion :

  1. Steep slopes: Steep slopes increase the rapidity and intensity of soil erosion.
  2. Torrential rainfall: Heavy rainfall forms gullies and ravines leading to a bad land topography.
  3. Strong winds: Winds, through the process of deflation, blow away layers of fine soil.
  4. Overgrazing: Overcropping and shifting cultivation renders the soil infertile.
  5. Deforestation: Deforestation exposes the area to soil erosion. Reckless cutting of trees has resulted in soil erosion by chos of the Shiwaliks.

Question 6.
State the method of soil management.
Answer:
Various methods are being practised for soil management :

  • Afforestation” Reforestation in old areas and afforestation in new areas are required to hold the soil. Surface run-off can be checked. Advance of deserts can be checked by planting trees along the margins of deserts.
  • Controlled grazing” This number of animals to be grazed on slopes should be according to the carrying capacity of the pastures. It gives time for the grass to grow again.
  • Terraced agriculture” Terraced cultivation on slopes should be practised to check the flow oT rain water.
  • Contour ploughing” Contour ploughing, terracing and bunding is done to check soil erosion on slopes. Ploughing is done at right angles to the slopes.

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 7.
Distinguish between Sial and Sima.
Answer:
The distinction between Sial and Sima :

Sial Sima
1. Sial is the uppermost layer on the Earth. 1. Sima is the layer found below sial.
2. It consists of silica and aluminium. 2. It consists of silica and magnesium.
3. It is a lighter layer with a density of 2.75. 3. It is a havier layer with a density of 5.
4. Continents are made of sial. 4. Ocean floors are made of sima.

Question 8.
How are rocks useful to man?
Answer:

  • Building materials: Rocks like granite, sandstone, slate and limestone are used in building roads and houses. Marble is used in more expensive building decoration.
  • Fossils: Fossils are found in sedimentary rocks. They are very useful to us because they tell us about the past environment, about animals and plants that are no longer found on earth.
  • Tools and implements: Since early civilization, rocks and stone have been used to make tools and implements. Clay bricks have been used for house construction and stones for the construction of pyramids, temples and buildings.
  • Fertilizers: Potash, nitrates and phosphates found in sedimentary rocks are used in the manufacturing of fertilizers.

Question 9.
Classify the minerals available in the earth’s crust.
Answer:
Three classifications are there:

  1. Metallic Minerals: These have particles of metals like iron, copper, aluminium, gold, silver, etc.
  2. Non-Metallic Minerals: These don’t contain particles of metal like Sulphur, Abhrak, Gypsum, Potassium, etc.
  3. Power Minerals: We get power and energy from such minerals which drive vehicles and run factories for us. Coal, Petrol, Natural gas, etc. are considered power minerals.

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 10.
In which category Mica is classified, for what purpose is it used?
Answer:
It is a non-metallic mineral. It has many uses:

  1. Used in electric goods making industry.
  2. Used mostly in lamp chimneys, colours, rubber, paper, medicines, vehcies and transparent sheet industry, etc.
  3. Slim sheets of this mineral are put in electric motors as insulator.

Comparison Type Questions

Question 1.
Distinguish between Rocks and Minerals.
Answer:
The distinction between rocks and minerals :

Rock Minerals
1. They are solid materials that make up earth’s crust. 1. They are solid and crystalline materials that for m the rocks.
2. Rocks have physical properties but do not have any definite chemical make-up. 2. They have physical properties and chemical make-up.
3. Rocks differ from each other on the basis of mineral content arid mode of formation. 3. Minerals differ from each other on the basis of elements or compounds of which they are constituted.
4. Based on formation, rocks can be divided into 3 main groups: igneous, sedimentary and metamorphic. 4. Based on formation there are above 2000 minerals that combine in different ways .to form rocks.

Question 2.
Distinguish between Igneous and Sedimentary rocks.
Answer:
The distinction between Igneous and Sedimentary rocks :

Igneous Rocks Sedimentary Rocks
1. They are called primary rocks. 1. They are called secondary rocks.
2. They are formed from the cooling and solidification of lava. 2. They form from deposits or sediments obtained from weathering and erosion of other rocks.
3. They do not contain any fossils. 3. They contain fossils.
4. They are rarely layered. 4. They are always layered.
5. Basalt, rhyolite, granite and gabbro are examples of these rocks. 5. Sandstone, shale, gravel and conglomerate are examples of these rocks.

Long Answer Type Questions

Question 1.
Describe the process of soil formation and the factors influencing it.
Answer:
The physical, chemical and organic changes that take place in the exposed rock over a long period of time lead to formation of soils.

Following factors influence this process of soil formation :

  1. Climate: Weathering depends on and is influenced by climate. It is the climate that causes disintegration of rock on account of differences in temperature and moisture.
  2. Rock Types: Parent rock and its type determines the rate of weathering and erosion. For example, sedimentary rock may be disintegrated quickly as well as cause form ation of soil and be a source of humus content in soil,
  3. Vegetation: Roots of plants help in weathering. The vegetation also provide materials for decomposition and formation of soils.
  4. Slope of land: Slope of land and general topography affect deposition and erosion of materials oi weathering. They may also form transported and residual soils.
  5. Time: The changes that lead to formation of soil are spread over thousands to millions of years. -The soils also undergo drastic changes with the passage of time.

PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth

Question 2.
With the help of a diagram, describe the interior of the earth.
Answer:
A diagram showing the interior of the earth is given ahead :
PSEB 7th Class Social Science Solutions Chapter 2 The Internal and External Face of the Earth 5
From the diagram it will be noticed that density goes on increasing towards the interior of the earth. Three main divisions of the interior of the earth are crust, mantle and core. Each of these three divisions has upper and lower part. Like density, temperature and pressure increase with the increase in depth inside the earth.

Crust: The thickness of the crust is 4-7 km below the seafloor and about 35 km below the continents. Beneath the mountain, the crust is 70 km thick. Continents are however made of a lighter material and rise above the oceanic crust.
Mantle: It extends upto 2900 km. The upper part is only about 100 km thick forming part of the lithosphere. The lower Mental is in a semi-plastic state.
Core: It has a radius of 3470 km and its upper part is in a liquid state and the lower part has enormous heat and is highly compressed, therefore at a solid rate. Iron and nickel are said to be the constituents of the Inner Core.

PSEB 7th Class Social Science Solutions Chapter 1 Environment

Punjab State Board PSEB 7th Class Social Science Book Solutions Geography Chapter 1 Environment Textbook Exercise Questions and Answers.

PSEB Solutions for Class 7 Social Science Geography Chapter 1 Environment

SST Guide for Class 7 PSEB Environment Textbook Questions and Answers

I. Give answers to the following questions approximately in 1-15 words.

Question 1.
What do you understand by environment?
Answer:
The environment is the surroundings of an organism. It is not the same everywhere. It changes according to the physical factors of some area, i.e. temperature and rainfall which are not the same everywhere.

Question 2.
Which are the main spheres of the environment?
Answer:

  1. Atmosphere,
  2. Lithosphere,
  3. Hydrosphere,
  4. Biosphere.

PSEB 7th Class Social Science Solutions Chapter 1 Environment

Question 3.
How man affects the environment?
Answer:
Man affects the environment in the following ways :

  1. Deforestation’for procuring agricultural land.
  2. Making dams on rivers and changing the direction of- water towards deserts.
  3. Mining to get minerals from the earth.

Question 4.
Write down the names of layers of the earth.
Answer:
The earth has three crusts

  1. Sial
  2. Mantel (Sima)
  3. Nife.

II. Fill in the Blanks :

Question 1.
Environment has been divided in __________ spheres.
Answer:
Four

Question 2.
The SIAL layer of the earth is made up of the material which is rich in and __________
Answer:
Silicon and Aluminium

Question 3.
NiFe is made up of the material which is rich in __________ and __________ elements.
Answer:
Nickel and Ferrous

PSEB 7th Class Social Science Solutions Chapter 1 Environment

Question 4.
The different types of species of animals is known as __________
Answer:
Biodiversity

Question 5.
__________ portion of earth has been covered by hydrosphere.
Answer:
Three fourth.

III. Activity:

Question 1.
Make a list of factors which has effect over the environment.
Answer:

  1. Relief
  2. Temperature
  3. Rainfall
  4. Degradation Processes
  5. Human factors.

PSEB 7th Class Social Science Guide Environment Important Questions and Answers

Multiple Choice Questions :

Question 1.
Which is not a natural ecosystem?
(a) Desert
(b) Forest
(c) Aquarium
(d) None of the above.
Answer:
(c) Aquarium.

PSEB 7th Class Social Science Solutions Chapter 1 Environment

Question 2.
Choose the correct answer out of the three alternatives given :
(a) Hydrosphere
(b) Biosphere
(c) Lithosphere
(d) Atmosphere.
Answer:
(b) Biosphere.

Question 3.
Hard top layer of the earth is called :
(a) Core
(b) Mantle
(c) Crust
(d) Earth.
Answer:
(c) Crust.

Question 4.
Which is a large ecosystem?
(a) Desert
(b) Buildings
(c) Roads
(d) Railways.
Answer:
(a) Desert.

Question 5.
Which is a human made environment?
(a) Mountain
(b) Sea
(c) River
(d) Road.
Answer:
(d) Road.

Fill in the Blanks :

Question 1.
Environment has been divided in __________ sphere.
Answer:
Four

Question 2.
__________ portion of earth has been covered by hydrosphere.
Answer:
Three fourth

PSEB 7th Class Social Science Solutions Chapter 1 Environment

Question 3.
__________ is a human made environment,
Answer:
Road

Question 4.
On __________ june every year world environment day is celebrated.
Answer:
5

Question 5.
__________ environment is the world of nonliving things.
Answer:
Biotic.

True / False :

Question 1.
The combination of Biosphere and physical environment is called ecology.
Answer:
True

Question 2.
The different types of species of animals is known as Biodiversity.
Answer:
True

PSEB 7th Class Social Science Solutions Chapter 1 Environment

Question 3.
Domain of water is called Biosphere.
Answer:
False

Question 4.
The world of living things are called biotic environment.
Answer:
True

Question 5.
Physical environment includes non-living elements.
Answer:
True.

Very Short Answer Type Questions

Question 1.
Name the three realms of the earth.
Answer:
The environment on the earth consists of three major elements-land, water and air. All these elements are very important and lithosphere, hydrosphere and atmosphere are three realms of the earth.

Question 2.
When is the world environment day celebrated?
Answer:
On 5 June.

PSEB 7th Class Social Science Solutions Chapter 1 Environment

Question 3.
What do you mean by Habitat?
Answer:
On the basis, of lithosphere, hydrosphere and atmosphere, a different type of biosphere is created for flora and fauna. Like humans, these also depend upon their environment which is called Habitat.

Question 4.
What do you mean by Ecology?
Answer:
The combination of Bio-sphere and physical environment is called Ecology.

Question 5.
How did the different spheres of the earth come into existence?
Answer:
The earth was a gaseous formation. The gases melt, become cold and solidified. The gaseous elements became atmosphere, watery elements became hydrosphere and solid particles became lithosphere.

Question 6.
What is atmosphere?
Answer:
Around the earth, there is a roundabout of earth which is several hundred kms wide. This is called Atmesphere. This roundabout is about 1600 km in radius but 99% of inhalable air (oxygen) is in the 32 km radius only.

Question 7.
What are the main elements of atmosphere?
Answer:
Temperature, humidity, air pressure, etc.

Question 8.
Describe the distribution of land and wq£er on earth.
Answer:

  • Land-29%,
  • Water-71%.

Question 9.
What is lithosphere? Write two features.
Answer:
The outer solid part of earth’s surface is called lithosphere.

Features:

  • Its thickness is 80-100 km.
  • Its thickness is more on land and less in water.

PSEB 7th Class Social Science Solutions Chapter 1 Environment

Question 10.
What is the utility of lithosphere?
Answer:

  • It provides us forests.
  • It provides grasslands for grazing.
  • It provides land for Agriculture.
  • It provides land for settlement.
  • It is a source of mineral wealth.

Question 11.
Name four types of water bodies included in Hydrosphere.
Answer:
Rivers, lakes, seas, oceans.

Question 12.
State two functions of Atmosphere.
Answer:

  1. It provides life-support gases.
  2. It keeps the earth’s temperature moderate.
  3. It protects us from hot-ultraviolet rays of the sun.

Question 13.
Give four examples of ecosystems.
Answer:

  1. A large rain forest
  2. A grassland
  3. A desert
  4. A mountain.

PSEB 7th Class Social Science Solutions Chapter 1 Environment

Question 14.
Differentiate between Natural and Human Environment.
Answer:

Natural environment Human environment
1. Land, water, air, plants and animals comprise the natural environment. 1. Individual, family, community, education religion,comprise the human environment.
2. It is essential for the existence of plant and human life. 2. It provides knowledge and technology to utilise the natural environment.

Question 15.
Distinguish between Physical and Biological environment.
Answer:

Physical Environment Biological Environment
1. Land, water, air and inorganic elements form the physical environment. 1. Plants, animals (including man) and organisms form biological environments.
2. It is essential for the existence of plants and human life. 2. It provides food and other materials for human beings.
3. It includes non-living elements. 3. It includes all living elements.
4. The physical environment influences human activities. 4. The physical and human environment interact with each other.

Question 16.
What is Biosphere? Write its two components.
Answer:
Plants and animals together form biospljere or the living world. It is narrow zone on the earth where land, water and air comes in contact with each other to support life.

Question 17.
By which name we call the sphere, that is product of interaction of three spheres? Write in brief. ‘ ‘
Answer:
The sphere made up by the combination of three spheres is called biosphere. It is made up of atmosphere, lithosphere and hydrosphere. Biosphere is the most important sphere on the earth because here the effect of natural factors is quite visible.

PSEB 7th Class Social Science Solutions Chapter 1 Environment

Question 18.
What do you mean by changing environment?
Answer:
On the surface, environment is ever changing because all its elements undergo a change. These elements are interdependent. The changes in natural environment brings about changes in Biological environment.

Short Answer Type Questions

Question 1.
Name the uses of Environment.
Answer:

  • It provides the air we breath.
  • It provides water and drink.
  • It provides food we eat.
  • It provides land where we live.

Question 2.
From the earth’s surface till the deep inside, in how many parts has the earth been divided? Write each in brief.
Answer:

  1. Earth’s surface: It is the upper most part of earth. It is called Sial. It has mainly Silicon (Si) and Aluminium (Al).
  2. Mantle: It is the middle part of earth called Sima. Its main components are Silicon (Si) and Magnesium (Mg).
  3. Central part/Core: It is the deep inside of earth called Nife. It has more of Nickle (Ni) and Iron (Ferrous Fe).

PSEB 7th Class Social Science Solutions Chapter 1 Environment 1

Question 3.
What is the importance of oceans?
Answer:
The hydrosphere is the part of the earth’s surface, covered by water. Rivers, lakes, seas and oceans form this sphere. More than 70 per cent of the earth’s surface is covered with water. Continents are like vast islands floating in the oceans. On the other hand, oceans are the major links between landmasses. Water supports all forms of life on the earth and is very crucial for our survival.

Question 4.
‘Man modifies his environments’. Discuss.
Answer:
Human life is closely related to the environment, Man modifies environment according to his needs. He learnt to cultivate crops, domesticate animals and lead a settled life. He used raw materials to make finished goods.

PSEB 7th Class Social Science Solutions Chapter 1 Environment

Question 5.
Why is it necessary to study natural environment?
Answer:
The study of natural environment is necessary because it, provides us conditions for living like land, air, water and food. It affects our economic activities and basic needs of food, shelter and clothing. It is the basic life supporting system on the earth.

Question 6.
‘Most of the environmental problems are man-made.’ Explain.
Answer:
Man is using water, land, soil and other resources at such an alarming rate that there will be serious shortage of these resources in the near future. Careless use may destroy them to such an extent that they may not be available to mankind. Man will have to live in harmony with the environment so that ecological balance is not disturbed.

Question 7.
‘Man has disturbed the environment.’ Discuss.
Answer:
Man has tried to exploit the resources of Biosphere. But he has disturbed the eco-system in this attempt. Human interference with the natural environment has modified or altered the ecosystem in many areas.

  1. Deforestation for cultivation has changed the habitat of the organisms living in the forests.
  2. It has resulted in soil erosion.
  3. Excessive cultivation, over-grazing, and shifting agriculture have increased the rate of soil erosion.
  4. Irrigation projects in dry areas have resulted into salinization of soil and spread of water borne diseases.
  5. Land, air and water have got polluted and have become unsuitable for human consumption.
  6. In recent years, environmental pollution and presence of chemicals in air, water and food has damaged human health.

PSEB 7th Class Social Science Solutions Chapter 1 Environment

Question 8.
‘The earth is a unique planet.’ Give reasons.
Answer:
The earth is a unique planet of the Solar System because its environment favours the evolution and survival of life to make it a life bearing layer or biosphere.

  • It is the only planet supporting plant and human life.
  • On the earth moderate temperatures (Mean temp. 15°C) are found. It is neither too hot like Mercury, nor too cold like Jupiter due to optimum distance of the earth from the sun.
  • The presence of oxygen nad nitrogen in the atmosphere around the earth favours the existence of life on the Earth. The atmosphere protects the earth from high temperatures.
  • The earth is a ‘watery planet’. Water cycle on the earth provides water for growth of all living beings. The earth is the home of man.

Question 9.
Why should we protect our environment?
Answer:

  1. Environment is our basic life support system. It provides the air we breathe, the water we drink, the food we eat and the land where we live.
  2. It provides us natural resources such as wood, fuel, energy and minerals.
  3. Most of the human activities affect the environment in one way or the other.
  4. Many parts of the environment have already been badly damaged by over use or irrational use of resources like forest, pastures and farms.
  5. If we continue to do so, the damage will be irreparable and the consequences will be very serious.

Question 10.
What are the biotic and abiotic components of the natural environment?
Answer:

  • Biotic component is the world of living organisms for example – plants and animals.
  • Abiotic components are non-living elements for example land and minerals etc.

PSEB 7th Class Social Science Solutions Chapter 1 Environment

Question 11.
How many types of environment are there? Give brief account.
Answer:
The environment is of three types-Physical, Cultural and Biological.

  • The physical environment is the prevailing natural conditions comprising the land, water and air.
  • The environment of lifeforms plants, animals including humans and other organisms is called biological environment.
  • Cultural environment includes man-made features like settlements, roads, industries etc.

Long Answer Type Question

Question 1.
Describe the four spheres of environment.
Answer:
Broadly we can divide the environment into four spheres atmosphere, lithosphere, hydrosphere and biosphere.
1. Atmosphere: The atmosphere is the thin layer of air that envelops our earth. It is very dynamic in nature, changes can take place every hour. These changes in the atmosphere produce weather and climate. The atmosphere is not uniform all through its width. There are several layers of the atmosphere. The atmosphere provides a setting in which all forms of life are created and sustained. The force of gravity exerted by the earth holds the atmosphere around it. The atmosphere protects us from scorching heat and harmful ultraviolet radiation.

2. Lithosphere: The lithosphere is the layer of the earth consisting of rock materials, extending both over the continents and ocean basins. The overage thickness of the lithosphere is about 100 km.

  • The lithosphere is composed of oceans and continents. It has two parts—Sial and Sima.
  • The lithosphere is the sphere which provides us land to settle, soils for plants and is a source of mineral wealth.

Four Spheres of The Earth
PSEB 7th Class Social Science Solutions Chapter 1 Environment 2

3. Hydrosphere: The hydrosphere is the part of the earth’s surface, covered by water. Rivers, lakes, seas, and oceans form this sphere. More than 70 percent of the earth’s surface is covered with water. Continents are like vast islands floating in the oceans. On the other hand, oceans are the major link between landmasses. Water supports all forms of life on the earth and is very crucial for our survival. Oceans provide us with food and minerals. Even in the sea-bed, deposits of minerals, oil, and gas are found.

4. Biosphere: The biosphere is a very narrow sphere of the earth that contains life. This sphere includes parts of the atmosphere, hydrosphere, and lithosphere. Most of the living organisms are it plants or animals on the earth are found on or near the surface of land or water surrounded by air. Thus the biosphere is a very narrow zone where life on this planet exists.