Question

For a gas $\frac{R}{C_v}=0.4$, where 'R' is the universal gas constant and 'C${}_v$' is molar specific heat at constant volume. The gas is made up of molecules which are

• A. rigid diatomic
• B. monoatomic
• C. non-rigid diatomic
• D. polyatomic

Answer 1

The correct option is A rigid diatomic

The given relation is $\frac{R}{C_v}=0.4$

$⟹$ $C_v=\frac{R}{0.4}=\frac{5}{2}R$

From $C_p=R+C_v$

We get $C_p=R+\frac{5}{2}R=\frac{7}{2}R$

$\therefore$ $\gamma =\frac{C_p}{C_v}=\frac{7/2}{5/2}=1.4$

Thus the gas must be made up of rigid diatomic molecules.