Question

Solve this:

23. A refrigerator, whose coefficient of performance is 4, extracts heat from the water inside it at the rate of 200 J/cycle. The amount of the heat exhausted to the room, per cycle is

(1) 250 J (2) 400 J (3) 680 J (4) 180 J

Answer 1

Dear Student
$$\begin{gathered} K=\frac{Q_L}{Q_H-Q_L}=\frac{200}{Q_H-200} \\ 4=\frac{200}{Q_H-200} \\ 4Q_H=200+800=1000 \\ {Q}_H=250J \end{gathered}$$
Regards