Questions and Answers S.J.T.U. Phase Transformation and Applications 8O=dU=Cidl dU=CydT V1,T1 V2,T2 dy CrdT dU =0 Ideal gas V1,T2 〔8) 20 atm 10 atm 20 atm 50L 50L ?L 10 atm 25C 25℃ 50L Adiabatic ? expansion SJTU Thermodynamics of Materials Spring 2010 ©X.J.Jin Lecture 3 Second law IPhase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2010 © X. J. Jin Lecture 3 Second law I Questions and Answers V1,T1 V2,T2 V1,T2 dU  0 Ideal gas   0        V T U dU  CV dT Q dU C dT dU  CV dT    V 20 atm 50 L 25 C 10 atm 50 L ? 10 atm 50 L ? 20 atm ? L 25 C Adiabatic expansion