Question

Consider the following two processes;
I. A heat source at $1200K$ loses $2500kJ$ of heat to a $sink$ at $800K$
II. A heat source at $800K$ loses $2000kJ$ of heat to a $sink$ at $500K$
Which of the following statements is true?

• A. Both the processes are reversible
• B. Process II is more irreversibel that Process I
• C. Process I is more irreversibel that Process II
• D. Irreversibility associated in both the processes are equal

Answer 1

The correct option is B Process II is more irreversibel that Process I

Process-I



Entropy change of universe-process$-1$
$\delta S_1=-\frac{Q_1}{T_1}+\frac{Q_1}{T_2}$
$=-\frac{2500}{1200}+\frac{2500}{800}$
$=-2.08+3.12$
$=1.04kJ/K$

Process-II


Entropy change of universe-process$-2$
$\delta S_2=-\frac{Q_2}{T_2}+\frac{Q_2}{T_2}$
$=-\frac{2000}{800}+\frac{2000}{500}$
$=-2.5+4$
$=1.5kJ/K$

Thus, $\Delta S_2>\Delta S_1$ process-II is more irreversible than process-I.