P–V plots for two gases during adiabatic processes are shown in the Fig. 5.6. Plots 1 and 2 should correspond respectively to
(a) He and O2
(b) O2 and He
(c) He and Ar
(d) O2 and N2
For adiabatic process we know PVγ = Constant.
As curve 2 is steeper its γ is greater.
γ = 5/3 = 1.67 for monoatomic gases (curve 2)
γ = 7/5 = 1.40 for diatomic gases (curve 1)
Correct Choice : b.
