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A power transmission line feeds input power at 2300 V to a step down transformer with its primary windings having 4000 turns. The output power is delivered at 230 V by the transformer. If the current in the primary of the transformer is 5 A and its efficiency is 90%, the output current would be:
- 45 A
- 35 A
- 25 A
- 50 A
Correct answer: 45 A
Solution
Input power = V_p x I_p = 2300 x 5 = 11500 W. Output power = 0.9 x 11500 = 10350 W. Output current = P_out/V_out = 10350/230 = 45 A.
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