A gas in a closed container undergoes the cycle $\mathrm{ABCA}$ as shown in the figure. The net heat…
A gas in a closed container undergoes the cycle $\mathrm{ABCA}$ as shown in the figure. The net heat released by the gas after it has undergone 20 cycles is
$3 \mathrm{~kJ}$
$2 \mathrm{~kJ}$
$1.5 \mathrm{~kJ}$
$4.5 \mathrm{~kJ}$
Solution
As process is cyclic
$
\begin{aligned}
\Delta \mathrm{Q} & =\Delta \mathrm{W} \\
\Rightarrow \Delta \mathrm{Q} & =(\text { Area enclosed by } \mathrm{P}-\mathrm{V} \text { diagram }) \times 20
\end{aligned}
$
$\begin{aligned} & =\left(\frac{1}{2} \times 20 \times 15\right) \times 20 \\ & =3000 \mathrm{~J} \\ & =3 \mathrm{~kJ}\end{aligned}$
