STANDARDPhysics-Electromagnetic Induction
STANDARD Physics Transformers MCQ Question
Type: MCQ-numerical-Medium-Class 12
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
0.27 A
B
2.7 A
C
3.7 A
D
0.37 A
Correct Answer
Option A
Detailed Explanation
Using the power equation P = VI, the secondary current Iₛ = 60/12 = 5 A. For an ideal transformer, VₚIₚ = VₛIₛ. Solving for Iₚ gives Iₚ = (VₛIₛ)/Vₚ = (12*5)/220 = 0.27 A.
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