Q 12-07-005NEETNEET 2023Top questionEasy
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?
Answer: (A) $0.27$ A
Concept. Ideal transformer: input power $=$ output power.
Step 1. Primary current.
$$I_p = \frac{60}{220} \approx 0.27\ \text{A}$$
Answer. $0.27$ A (Option A).
Solution by Sreeraj P, M.Sc Physics