Q139 / 160 · TS EAMCET 2022 (20 Jul Shift 2) · Physics
A gas system is taken through the thermodynamic cyclic
process 1 → 2 → 3 → 1 as shown below. The amount of
heat released by the system is
- Correct answerA$-\mathrm{P} \frac{\mathrm{V}}{2}$
- B$\mathrm{PV}$
- C$\frac{P V}{2}$
- D$\frac{-3 \mathrm{PV}}{2}$
Solution
As process is cyclic
$\begin{aligned}
& \Delta \mathrm{U}=0 \\
& \Delta \mathrm{Q}=\Delta \mathrm{W} \\
& =\text { Area enclosed by curve } \\
& =\frac{1}{2} \times \mathrm{V} \times \mathrm{P}=\frac{\mathrm{PV}}{2}
\end{aligned}$
As process is clockwise, so $\Delta \mathrm{W}$ and $\Delta \mathrm{Q}$ is positive i.e. $\frac{\mathrm{PV}}{2}$ amount of heat is absorbed or $-\frac{\mathrm{PV}}{2}$ amount is released.
Hence, the correct answer is option: 'A'.