Question

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

• A. $150kcal$
• B. $450kcal$
• C. $350kcal$
• D. $250kcal$

Answer 1

The correct option is B $450kcal$

The efficiency of the cycle is given as $\eta =1-\frac{T_2}{T_1}=\frac{Q_1-Q_2}{Q_2}$. Here $T_1$ is the temperature of the source and $T_2$ is the temperature of the sink. $Q_1$ is the heat gained from the source and $Q_2$ is the heat rejected to the sink. Thus we get $1-\frac{375}{500}=0.25=\frac{600-Q_2}{600}$
or $Q_2=600-150=450kcal$