Question

1. How does the heat H produced by a current passing through a fixed resistance wire depend on the magnitude

of current I ?

2. If the current passing through a conductor is doubled, what will be the change in heat produced ?

3. Name two effects produced by electric current.

4. Which effect of current is utilised in an electric light bulb ?

5. Which effect of current is utilised in the working of an electric fuse ?

6. Name two devices which work on the heating effect of electric current.

7. Name two gases which are filled in filament type electric light bulbs.

8. Explain why, filament type electric bulbs are not power efficient.

9. Why does the connecting cord of an electric heater not glow hot while the heating element does ?​

Answer 1

`1. The heat produced (H) by a current passing through \\ a fixed resistance wire depends on the square of the \\ magnitude of the current (I^2). \\ In mathematical terms, H ∝ I^2. \\ </p><p></p><p>2. If the current passing through a conductor is doubled, \\ the change in heat produced will be four times greater (2^2 = 4 times). \\ This is because the heat produced is proportional to the \\ square of the current, so doubling the current results in four times \\ the heat being produced.`

Answer 2

1.Ans:- The heat produced by a current passing through a fixed resistance wire (H) is directly proportional to the square of the magnitude of the current (I²).

2.Ans:- If the current passing through a conductor is doubled, the heat produced will increase by a factor of four (2²).

3.Ans:- Two effects produced by electric current are the heating effect (production of heat) and the magnetic effect (creation of a magnetic field).

4.Ans:- The heating effect of current is utilized in an electric light bulb to generate light and heat.

5.Ans:- The heating effect of current is utilized in the working of an electric fuse, where the fuse wire heats up and melts to break the circuit during excessive current flow.

6. Ans:- Two devices that work on the heating effect of electric current are electric heaters and toasters.

7. Ans:- The two gases commonly filled in filament-type electric light bulbs are nitrogen and argon.

8.Ans:- Filament-type electric bulbs are not power efficient because they primarily produce light through incandescence, which releases a significant amount of energy as heat, making them less energy-efficient compared to other lighting technologies like LEDs.

9. Ans:- The connecting cord of an electric heater does not glow hot because it has a lower resistance compared to the heating element. The majority of the current flows through the high-resistance heating element, generating heat, while the connecting cord carries a smaller current and does not heat up as much.