Q. The coefficient of performance of a refrigerator is 5. If the temperature inside freezer is –20°C, the temperature of the surroundings to which it rejects heat is :
A) 21°C
B) 31°C
C) 41°C
D) 11°C
Explanation
[Solution] $\beta = \frac{T_2}{T_1 - T_2} = 5$ with $T_2 = 253$ K gives $T_1 \approx 304$ K ≈ 31°C. Answer (2).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.