Question

A Carnot engine operates with a source at 500 K and sink at 375 K. If the engine takes 600 K cal of heat in one cycle, the heat rejected to sink per cycle is

• A. 250 kcal
• B. 350 kcal
• C. 450 kcal
• D. 550 kcal

Answer 1

Answer: (C)

450 kcal

In a Carnot's cycle, work done and heat energy supplied are related as
$\frac{W}{Q_H}=1-\frac{T_{sink}}{T_{source}}$
$W=600(1-\frac{375}{500})=150kcal$
and $W=Q_H-Q_C$
$Q_C=Q_H-W=600-150=450kcal$
Option C.