A reversible engine operating between 500 K and 300 K has the same efficiency as a reversible engine operating between 400 K and what lower temperature?
A) 200 K
B) 220 K
C) 240 K
D) 260 K
E) 280 K

Question

Quizplus · Accepted Answer

The efficiency of a reversible engine is given by 1 - (T_cold/T_hot). For the first engine: 1 - (300/500) = 0.4. For the second engine: 1 - (T_lower/400) = 0.4. Solving for T_lower gives T_lower = 240 K.

A Reversible Engine Operating Between 500 K and 300 K