n mole of a perfect gas undergoes a cyclic ABCA (see figure) consisting of the following processes.
A → B ∶ Isothermal expansion at temperature T so that the volume is doubled from V1 to V2 = 2V1 and pressure changes from P1 to P2.
B → C ∶ Isobaric compression at pressure P2 to initial volume V1.
C → A ∶ Isochoric change leading to change of pressure from P2 to P1.
Total work done in the complete cycle ABCA is:
1
0
2
nRTln 2
3
nRT\(\left( {\ln 2 + \frac{1}{2}} \right)\)
4
nRT\(\left( {\ln 2 - \frac{1}{2}} \right)\)