General Science Important Questions Chapter 4 Current Electricity and Magnetism Class 8 Maharashtra Board

Imp Questions For All Chapters – General Science Class 8

Short Questions

1. What is an electric current?

• The flow of electric charge in a circuit is called electric current.

2. What is the SI unit of electric current?

• The SI unit of electric current is Ampere (A).

3. What is a dry cell?

• A dry cell is a portable source of electric energy that uses chemical reactions to produce electricity.

4. What are the two terminals of a dry cell?

• A dry cell has a positive terminal (carbon rod) and a negative terminal (zinc case).

5. What is potential difference?

• The difference in electric potential between two points in a circuit is called potential difference.

6. What is the SI unit of potential difference?

• The SI unit of potential difference is Volt (V).

7. What is an electric circuit?

• A closed path in which electric current flows is called an electric circuit.

8. What is a battery?

• A battery is a combination of two or more cells connected to produce a higher voltage.

9. How does electricity flow in a circuit?

• Electricity flows from the negative terminal to the positive terminal of a battery.

10. What is an electromagnet?

• A temporary magnet made by passing electric current through a coil is called an electromagnet.

11. Who discovered the magnetic effect of electric current?

• Hans Christian Oersted discovered the magnetic effect of electric current.

12. What happens when current flows through a wire?

• A magnetic field is created around the wire.

13. What is an electric bell?

• An electric bell is a device that uses an electromagnet to produce sound.

14. Where are lead-acid batteries used?

• Lead-acid batteries are used in cars, trucks, and UPS systems.

15. What is the role of a switch in a circuit?

• A switch is used to open or close a circuit to control the flow of electricity.

Long Questions

1. Explain the working of a dry cell.

• A dry cell has a zinc container (negative terminal) and a carbon rod (positive terminal) with an electrolyte in between. Due to chemical reactions, electrons flow, creating an electric current in a circuit.

2. How does an electric bell work?

• When current flows, the electromagnet attracts an iron strip, causing the striker to hit the gong. The circuit then breaks, the strip returns, and the process repeats to produce sound.

3. Why does a bulb glow in a circuit?

• When the circuit is complete, electric current flows through the filament of the bulb, heating it. The filament then glows, producing light and heat.

4. What is the difference between a cell and a battery?

• A cell is a single unit that generates electricity through chemical reactions. A battery is a combination of multiple cells connected to provide higher voltage.

5. How is an electromagnet different from a permanent magnet?

• An electromagnet is a temporary magnet that works only when electricity flows. A permanent magnet always has magnetism and does not need electricity.

6. What is the magnetic effect of electric current?

• When electric current passes through a wire, a magnetic field forms around it. This effect was first observed by Hans Christian Oersted.

7. Why does a car battery have more than one cell?

• A car battery has multiple cells connected in series to provide a higher voltage. This high voltage is needed to start and operate the vehicle.

8. What happens if a circuit is broken?

• If a circuit is broken, electric current cannot flow. As a result, electrical devices like bulbs, fans, and bells will stop working.