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NEET PHYSICSEasy

A 12 V, 60 W lamp is connected to the secondary of a step-down transformer, whose primary is connected to AC mains of 220 V. Assuming the transformer to be ideal, what is the current in the primary winding?

A

0.37 A

B

0.27 A

C

2.7 A

D

3.7 A

Step-by-Step Solution

According to the sources, for an ideal transformer, the power input to the primary is equal to the power output from the secondary (Pp=PsP_p = P_s) . The power consumed by the lamp in the secondary circuit is given as 60 W. Therefore, the power in the primary circuit is also 60 W. Using the power formula P=VIP = V I, we can find the primary current (IpI_p) by dividing the primary power by the primary voltage: Ip=Pp/Vp=60 W/220 V0.2727I_p = P_p / V_p = 60 \text{ W} / 220 \text{ V} \approx 0.2727 A, which rounds to 0.27 A.

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