A refrigerator uses $100 \mathrm{~W}$ of electric power and discards $600 \mathrm{~W}$ of thermal power into the kitchen. What is its coefficient of performance?
A) 0.17
B) 0.20
C) 5
D) 6
E) Other (specify)
F) Impossible because it violates conservation of energy.

Question

Quizplus · Accepted Answer

The coefficient of performance (COP) for a refrigerator is given by the ratio of the heat removed from the refrigerated space (Q_c) to the work input (W), COP = Q_c/W. Here, Q_c is the thermal power discarded into the kitchen, which is 600 W, and W is the electric power used, which is 100 W. Therefore, COP = 600 W / 100 W = 6.

A Refrigerator Uses 100 W100 \mathrm{~W}100 W Of Electric Power and Discards 600 W600 \mathrm{~W}600 W

A Refrigerator Uses $100 \mathrm{~W}$ Of Electric Power and Discards $600 \mathrm{~W}$