Question

20J of heat energy is extracted from a cold reservoir when 30J of work is done on a refrigerator. What is the coefficient of the refrigerator?

(a) 2/3

(b) 5/3

(c) 3/5

(d) 1/3

I have been asked this question during an interview.

This question is from Thermodynamics topic in portion Thermodynamics of Physics – Class 11

Answer 1

Right choice is (a) 2/3

Explanation: The coefficient of a refrigerator is defined as α = Q2/W,                                                                 where Q2 is heat extracted from a cold reservoir and W is work done.   

α = 20/30 = 2/3.