This PSEB 7th Class Science Notes Chapter 14 Electric Current and Its Effects will help you in revision during exams.
PSEB 7th Class Science Notes Chapter 14 Electric Current and Its Effects
→ Electrical components can be represented by symbols that are very convenient in representation.
→ The circuit diagram is a diagrammatic representation of an electrical circuit.
→ The symbol of an electric cell is two parallel lines, one of which is a long line and the other a short line.
→ A battery is a combination of two or more cells.
→ Batteries are used in flashlights, transistors, radios, toys, TVs, remote controls, etc.
→ Electric bulbs have a thin filament, which illuminates by the flow of electric current. This is due to the heating effect of the electric current.
→ In electric heaters, room heaters, and testers heating effect of current is used.
→ An electric fuse consists of a special wire having a low melting point so that when it is placed in an electric circuit carrying heavy current it melts.
→ Electrical fuses are used in an electric circuit to save electrical appliances from fire or any other damage when heavy current flows in the circuit.
→ Any metallic wire acts as a magnet when an electric current passes through it. This effect of electric current is called its magnetic effect.
→ When current is passed through an iron bar placed in a coil, it acts like a magnet. A magnet made in this way is called an electric magnet.
→ An electromagnet is a magnet and when an electric current is switched off, it loses its magnetic properties.
→ Electromagnets are used in many devices, such as electric bells and magnetic cranes, etc.
→ Conductor: A substance that allows an electric current to pass through it, is called a conductor.
→ Resistance: A substance that opposes the flow of electric current from passing through it, is called resistance.
→ Switch: This is a simple device that is used to complete the path for the flow of current or to break it, is called a switch.
→ Circuit: The path which electric current follows from the positive terminal of cell/battery to its negative terminal via bulb, resistance, and switch.
→ Bulb: A simple device that converts electrical energy into light energy.
→ Filament: A thin wire of tungsten metal that gets heated due to the passage of electric current and emits light, is called Filament.
→ Battery: This is a combination of two or more electrochemical cell that converts their chemical energy into electrical energy.
→ Electromagnetism: Place a soft piece of iron inside the coil and pass an electric current through the coil. With this comes the property of a magnet inside a piece of iron. This technique is called electromagnetism.
→ Electric bell: A mechanical device that works on the principle of an electromagnet and produces repeated sounds on passing electric current.
→ Electric Crane: It consists of a crane with a large powerful magnet attached to one end that is used to lift, heavy objects made of iron and move them from one place to another place.