A cyclic process for 1 mole of an ideal gas is shown in the V−T  diagram. The work done in AB , BC  and CA  respectively are

During AB, process is isochoric. ∴   ΔV=0           ∴   W=0 During BC, process is isothermal∴   ΔT=0           ∴   W=RT 2lnV 2V 1 During CA, process is isobaric. So , pressure is constant.∴   W=P(V 1−V 2) But PV 1=RT 1 ∴   P=RT 1V 1=RT 2V 2             ∴   W=RT 1V 1(V 1−V 2)=RT 2V 2(V 1−V 2)