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A step-down transformer connected to an ac mains supply of 220 V is made to operate an 11 V, 44 W lamp. Ignoring power losses in the transformer, what is the current in the primary circuit?

Asked in NEET 2021 · Transformers

Answer: (1) 0.2 A

Step-by-step solution

An ideal transformer delivers the same power on both sides, so the primary draws 44 W.

Iₚ=P/(Vₚ)=(44)/(220)=0.2 A.

As a check, the secondary carries (44)/(11)=4 A, and the turns ratio of

(220)/(11)=20 divides that to 4/(20)=0.2 A.

Why the other options are wrong

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