9. An ideal gas expands isothermally from a volume
V1 to V2 and then compressed to original volume V1 adiabatically. Initial pressure is P1 and final pressure is P3 . The total work done is W. Then
(a) P3 > P1 ,W > 0 (b) P3 < P1 ,W < 0
(c) P3 > P1 ,W < 0 (d) P3 = P1 ,W = 0
Answer-c
(10)