Question

A Carnot cycle operates between temperature limits of 900 and 300K The best supplied at the high muncrature is 4 MJ. Calculate the change in entropy during the heat addition and rejection processes the heat rejection and the work output

Answer 1

Answer:Work=$\frac{8}{3}MJ$

Explanation:

Cycle is operated between 900 and 300 K

heat supplied at high temperature is 4MJ

Let heat supplied be $Q_1$

and heat rejected is $Q_2$

$\eta =1-\frac{T_L}{T_H}=1-\frac{Q_2}{Q_1}$

$\frac{Q_2}{Q_1}=\frac{T_L}{T_H}$

$Q_2=4\times \frac{300}{900}=\frac{4}{3} MJ$

Change in entropy during heat addition $\Delta =\frac{Q_1}{T_H}=\frac{4\times 10^3}{900}=4.44 KJ/K$

Change entropy during heat rejection $\Delta =\frac{Q_2}{T_L}=-4.44 KJ/K$

$W=4-\frac{4}{3}=\frac{8}{3} MJ$