Q2 of 14 Page 56

Copper wires of the same length and thickness are connected to points A and B in all the three circuits. In circuit (a) copper wire is not coiled. In circuits (b) and (c), the copper wire is coiled. Observe the circuits and answer the following questions.



(a) When circuit (a) is switched on, what do you observe?


(b) When circuit (b) is switched on, what change do you observe in the intensity of light? Justify your answer.


(c) When circuit (c) is switched on, what change do you observe in the intensity of light? Justify your answer.

(a)The bulb in (a) glows brightly.

(b) The bulb in (b) glows brightly. There is no change in intensity as the power supply is DC. So, inductance has no role to play.


(c) The intensity of light reduces. The coiled wire behaves as an inductor and a back emf is generated. This reduces the effective voltage of the circuit.


More from this chapter

All 14 →
1


(a) Write down the name of parts numbered in the diagram.


(b) State the working principle of this device.

 3

The current in the secondary coil of a transformer is 1A and that in the primary is 0.5 A.

What type of a transformer is this?

 3

The current in the secondary coil of a transformer is 1A and that in the primary is 0.5 A.

If 200 V is available in the secondary coil of this transformer, what is the voltage in the primary?

 3

The current in the secondary coil of a transformer is 1A and that in the primary is 0.5 A.

Explain the working principle of a transformer.