Question

The efficiency of a carnot engine operating between reservoirs maintained at ${27}^{o}C$ and $-{123}^{o}C$ is

• A. $0.75$
• B. $0.4$
• C. $0.25$
• D. $0.5$

Answer 1

Answer: (D)

$0.5$

The carnot efficiency is given as $\eta =1-\frac{T_2}{T_1}$. Here $T_1$ is the temperature of the hot reservoir and $T_2$ is the temperature of the cold reservoir.
Thus, we get $\eta =1-\frac{-123+273}{27+273}=1-\frac{150}{300}=0.5$