During an adiabatic process, the pressure of a gas is found to be proportional to the cube of its temperature. The ratio of CpCυ for the gas is
53
32
43
2
P∝T3
PT3= constant ---(i)
For an adiabatic process,
PTγ/1−γ=constant ---(ii)
Comparing (i) and (ii), we get
γ1−γ=−3 γ=−3+3γ −2γ=−3 or γ=32 As γ=CpCυ ∴ CpCυ=32