
Three moles of an ideal monotomic gas performs a cycle \(A B C D A\) as shown in the figure. The…

- \(1200 \mathrm{R}\)
- \(3600 \mathrm{R}\)
- \(2400 \mathrm{R}\)
- \(2000 \mathrm{R}\)
Solution

Given, number of moles of an ideal monoatomic gas, \(n=3\), temperature of the gas of state \(A, T_A=400 \mathrm{~K}\), temperature of the gas at state \(B, T_B=800 \mathrm{~K}\), temperature of the gas at state \(C, T_C=2400 \mathrm{~K}\), and temperature of the gas at state \(D, T_D=1200 \mathrm{~K}\), Now, work done by the gas during this cycle is, \(W=n R \Delta T\) ( \(\therefore\) Work done in a isothermal process) So, \(W_{\text {nct }}=W_{A \rightarrow B}+W_{B \rightarrow C}+W_{C \rightarrow D}+W_{D \rightarrow A}\) \(\begin{aligned} & W_{\text {net }}=n R\left[\left(T_B-T_A\right)+\left(T_C-T_B\right)+\left(T_D-T_C\right)-\left(T_D-T_A\right)\right] \\ & W_{\text {net }}=3 R[0+(2400-800)+0-(1200-400)] \\ & W_{\text {net }}=3 R \times[1600-800] \\ & W_{\text {net }}=3 R \times 800, W_{\text {net }}=2400 R \end{aligned}\) So, the work done by the gas during, \(A \rightarrow B \rightarrow C \rightarrow D\) cycle is \(W_{\text {net }}=2400 R\).
Asked in: AP EAMCET 2019 (22 Apr Shift 1)