Electricity Circuits and Their Components Class 7 Long Question Answer

Electricity Circuits and Their Components Class 7 Long Question Answer

Electricity Circuits and Their Components Class 7 Long Question Answer

Question 1.

Describe the construction and working of an electric cell.

Answer:

An electric cell consists of chemicals enclosed in a container, with two terminals : positive (+) and negative (-). It is a portable energy source. When connected in a circuit, it drives electric current from the positive to the negative terminal. The chemical reactions inside generate electricity.

Question 2.

Explain how a filament bulb produces light.

Answer:

A filament bulb contains a thin wire called the filament made of tungsten. When current flows through the filament, it gets heated due to resistance and glows, producing light. The bulb glows only in a complete circuit. It gets hot but also provides illumination.

Question 3.

Explain how an LED differs from a normal bulb.

Answer:

An LED (Light Emitting Diode) produces light when current passes in one direction. It is more energy-efficient and lasts longer than a filament bulb. An LED needs correct polarity to function. Unlike a filament bulb, it does not get very hot.

Question 4.

Write the difference between

(i) A.C. and D.C. currents.

(ii) Incandescent lamp and LED lamp.

Answer:

(i) A.C. (Alternating current): Current changes direction again and again.

D.C. (Direct current): Current flows only in one direction.

(ii) Incandescent lamp: Gives light by heating a wire filament, uses more electricity.

LED lamp: Give light using tiny dioides, saves electricity and lasts longer.

Question 5.

Write the precautions while using electrical equipments.

Answer:

Precautions while using electrical equipments:

1. Never touch switches or wires with wet hands.
2. Always check wires for damage before use.
3. Do not overload a socket with too many plugs.
4. Switch off the main supply before repairing or touching any electrical device.