Work done by a Carnot engine operating between temperatures 127°C and 27°C is 2 kJ. The amount of heat transferred to the engine by the reservoir is:
Options

Question

Work done by a Carnot engine operating between temperatures 127°C and 27°C is 2 kJ. The amount of heat transferred to the engine by the reservoir is:

G1 Physics · Accepted Answer

Carnot efficiency is η = 1 - T(cold)/T(hot) Convert temperatures to kelvin: T(hot) = 127 + 273 = 400 K T(cold) = 27 + 273 = 300 K Therefore, η = 1 - 300/400 = 1/4 Efficiency is also η = W/Q(in) Given W = 2 kJ: Q(in) = W/η = 2/(1/4) = 8 kJ Hence option D follows.