Q. A 220-volt input is supplied to a transformer. The output circuit draws a current of 2.0 ampere at 440 volts. If the efficiency of the transformer is 80%, the current drawn by the primary windings of the transformer is
A) 5.0 ampere
B) 3.6 ampere
C) 2.8 ampere
D) 2.5 ampere
Explanation
(a) $\eta = \frac{V_{s}I_{s}}{V_{p}I_{p}} = 0.8 \Rightarrow I_{P} = \frac{(440)(2)}{(0.8)(220)} = 5\ A$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.