A transformer takes 2.0 A from a 230 V supply and delivers 9.0 A at 46 V. What is its efficiency?
Correct answer A. 90%
Explanation
Input power = 230 × 2.0 = 460 W; output power = 46 × 9.0 = 414 W. Efficiency = 414/460 × 100% = 90%.
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