
$\Delta \mathrm{Q}=\Delta \mathrm{W}+\Delta \mathrm{V}$
$\Delta \mathrm{W}=\frac{1}{2} \times\left(2 \mathrm{P}_{0}+\mathrm{P}_{0}\right) \times \mathrm{V}_{0}=\frac{3}{2} \mathrm{P}_{0} \mathrm{V}_{0}$
$\frac{\mathrm{PV}}{\mathrm{T}}=\mathrm{const}=\mathrm{nR}$
$\frac{P_{0} V_{0}}{T_{0}}=\frac{2 P_{0} 2 V_{0}}{T^{\prime}}$
$\mathrm{T}^{\prime}=4 \mathrm{T}_{\mathrm{o}}$
change in temperature $=3 \mathrm{T}_{0}$
$\Delta \mathrm{U}=\mathrm{n} \times \frac{3}{2} \mathrm{R} \times 3 \mathrm{T}_{0}=\frac{9}{2}\left(\mathrm{nRT}_{0}\right)=\frac{9}{2} \mathrm{P}_{0} \mathrm{V}_{0}$
$\Delta \mathrm{Q}=6 \mathrm{P}_{0} \mathrm{V}_{0}$
(image)
$(A)$ Process $I$ is an isochoric process $(B)$ In process $II$, gas absorbs heat
$(C)$ In process $IV$, gas releases heat $(D)$ Processes $I$ and $III$ are $not$ isobaric

