Question

An ideal refrigerator has a freezer at a temperature of $-{13}^{\circ }C$. The coefficient of performance of the engine is 5. The temperature of the air (to which heat is rejected) will be:

• A. ${325}^{\circ }C$
• B. $325K$
• C. $39{}^{\circ }C$
• D. ${320}^{\circ }C$

Answer 1

Answer: (C)

$39{}^{\circ }C$

Given, $T_2=-{13}^{\circ }C=260Kand\beta =5$
$\beta =\frac{T_2}{T_1-T_2}$
$5=\frac{260}{T_1-260}$
$T_1=312K$
or $T_1=312K={39}^{\circ }C$