Question

A scientist say that the efficiency of his heat engine which operates at source temperature ${127}^{\circ }C$ and sink temperature ${27}^{\circ }C$ is $26$%, then

• A. It is impossible
• B. It is possible but less probable
• C. It is quite probable
• D. Data are incomplete

Answer 1

The correct option is A It is impossible

We know,

${\eta }_{max}=1-\frac{T_2}{T_1}=1-\frac{27+273}{127+273}=1-\frac{300}{400}=25\%$

Hence, 26$\%$ is impossible.