Question

What is the coefficient of performance of a refrigerator? Let Q1 be the heat released to hot reservoir, Q2 be the heat extracted from a cold reservoir & W be the work done on the refrigerator.

(a) Q1/W

(b) Q1/Q2

(c) Q2/W

(d) Q2/Q1

The question was asked at a job interview.

My doubt is from Thermodynamics in chapter Thermodynamics of Physics – Class 11

Answer 1

Right answer is (c) Q2/W

To explain I would say: Coefficient of performance of a refrigerator is defined as the ratio of heat extracted from the cold reservoir to the work done on the refrigerator.                                                                                                         It is denoted by α = Q2/W.