A power station sends 100 kW through cables of total resistance 5.0 Ω. What power is lost as heat in the cables if transmission is at 10 kV?
Correct answer D. 500 W
Explanation
Current I = P/V = 100 000/10 000 = 10 A. Power loss = I²R = 10² × 5.0 = 500 W. Using V²/R with the transmission voltage is incorrect, since that voltage is not across the cables.
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