Question

The efficiency of Carnot engine is $0.6$ . It rejects $20J$ of heat to sink. The work done by the engine is

• A. 20 J
• B. 30 J
• C. 33.3 J
• D. 50 J

Answer 1

Answer: (B)

Efficiency = $0.6$
Heat given to sink, $Q_2=20J$
$\eta =\frac{Q_1-Q_2}{Q_1}$
$0.6=\frac{Q_1-20}{Q_1}$
$0.6Q_1=Q_1-20$
$0.4Q_1=20$
$Q_1=50J$
Work done, $W=Q_1-Q_2=50-20$
$=30J$