Question

For a reversible process, which one is correct?

• A. \(\displaystyle \oint \frac{dQ}{T}>0\)
• B. \(\displaystyle \oint \frac{dQ}{T}<0\)
• C. \(\displaystyle \oint \frac{dQ}{T}=0\)
• D. \(\displaystyle \oint \frac{dQ}{T}=1\)

Hint:

For a reversible cyclic process, \(\oint \frac{\delta Q}{T}=0\).

Answer 1

The Correct Option is C

Concept:
For a reversible cyclic process, Clausius theorem states: \[ \oint \frac{\delta Q_{rev}}{T}=0 \]

Step 1: Understand entropy change.
For a reversible process: \[ dS=\frac{\delta Q_{rev}}{T} \]

Step 2: For a complete cycle.
Entropy is a state function. For a complete cycle, the system returns to the initial state. Therefore, \[ \oint dS=0 \]

Step 3: Substitute entropy expression. \[ \oint \frac{\delta Q_{rev}}{T}=0 \] \[ \therefore \text{Correct Answer is (C)} \]