Question

An ideal gas taken through process ABCA. If net heat supplied is 5 J, find work done in process $C \to A$.

• A. -5 J
• B. -10 J
• C. -15 J
• D. -20 J

Hint:

In a cycle, $\Delta U = 0$, so $Q = W$.

Answer 1

The Correct Option is C

Step 1: Concept
First Law for cyclic process: $Q_{net} = W_{net} = W_{AB} + W_{BC} + W_{CA}$.

Step 2: Analysis
From graph (P-V diagram):
- $W_{AB}$ (Isochoric) $= 0$.
- $W_{BC}$ (Isobaric) $= P \Delta V = 10(2 - 0) = 20$ J. (Assuming units from scan).

Step 3: Calculation
$5 = 0 + 20 + W_{CA} \implies W_{CA} = 5 - 20 = -15$ J.

Step 4: Conclusion
Hence, work done $C \to A$ is -15 J. Final Answer: (C)