Q3 of 14 Page 56

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?

The equation used to work out the power for the primary coil and the secondary coil of a transformer is:

P = V × I


where:


P is the power in watts, W


V is the potential difference in volts, V


I is the current in amperes (amps), A


Because the current is larger in the secondary coil of the transformer is larger as compared to that in primary coil.


This means the voltage in the secondary coil must be smaller in order to maintain constant power. Hence, the transformer which results in low voltage is called a step-down transformer.


More from this chapter

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1


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


(b) State the working principle of this device.

 2

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.

 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.