The correct option is C Cv(T1−T2)
Work done in an adiabatic expansion is given by
W=Rγ−1[T1−T2].....(i)
where, T1= initial temperature of the gas
T2= final temperature of the gas
γ= adiabatic constant
R= universal gas constant
Now, universal gas constant is given by:
R=Cp−Cv
Hence, equation (i) becomes
W=Cp−Cvγ−1[T1−T2]
Because, γ=CpCv, so we have
W=Cp−CvCpCv−1[T1−T2]
W=Cp−CvCp−CvCv[T1−T2]
or W=Cv(T1−T2).