Question

A refrigerator, whose coefficient of performance $K=5$, extracts heat from the cooling compartment at the rate of $250J/cycle$. What is the work done per cycle to operate the refrigerator? How much heat is discharged per cycle to the room which acts as the high temperature reservoir?

• A. $50J$
• B. $200J$
• C. $300J$
• D. none

Answer 1

Answer: (C)

$300J$

Work done per cycle $W=\frac{Q_2}{K}=\frac{250}{5}=50J$
Heat discharged per cycle $Q_1=Q_2+W=300J$