Work for the following process ABCD on a monoatomic gas is
The correct option is D. W=−2P0V0 ln2.
The process A--->B and C--->D are isobaric where as the process B---->C is isothermal.
Work done along AB:
WAB=−Pext(V2−V1)=−P0(2V0−V0)=−P0V0
Work done along BC:
WBC=−nRT ln(V2V1=−nRT ln(4V02V0)=−nRT ln(2)
Work done along CD:
WCD=−Pext(V2−V1)=−P(2V0−4V0)=2PV0
as BC is an isothermal process, from B→C there is increase in volume by two times so the pressure will be half of original
So, P=P02
∴WCD=P0V0
The total work done along the path ABCD is
W=WAB+WBC+WCD
W=−P0V0−nRT ln(2)+P0V0
W=−P0V0−2P0V0 ln(2)+P0V0
(As the process BC is an isothermal process, then at point B, 2P0V0=nRT)
W= −2P0V0 ln2.