An ideal gas is expanded from volume $V_1$ to $V_2$ along three different paths $O A, O B$ and $O C$

Question

An ideal gas is expanded from volume $V_1$ to $V_2$ along three different paths $O A, O B$ and $O C$, respectively, as shown in figure. If $\left|\Delta U_A\right|,\left|\Delta U_B\right|$ and $\left|\Delta U_C\right|$ be the magnitudes of change in internal energy for the three respective paths, then (assume that all the three curves lie above an isotherm passing through $O$ )

Professor PC Thomas Classes · Answer

Here $V_A=V_B=V_C=V_2$; since $P_A>P_B>P_C$, therefore, $T_A>T_B>T_C$ Thus, $\left|\Delta U_A\right|<\left|\Delta U_B\right|<\left|\Delta U_C\right|$