Question

For a rigid diatomic molecule, the universal gas constant $R = n C_{P}$ , where, $C_{P}$ is the molar specific heat at constant pressure and $n$ is a number. Hence, $n$ is equal to

• A. $0.2257$
• B. $0.4$
• C. $0.2857$
• D. $0.3557$

Answer 1

Answer: (C)

For rigid diatomic molecule
$\frac{C_{P}}{C_{V}}=\frac{7}{5}$
$\therefore \, \, C_{V}=\frac{5}{7}C_{P}$
Also $C_{P}-C_{V}=R$
$C_{P}-\frac{5}{7}C_{P}=R$
$\frac{2}{7}C_{P}=R \, $
$\therefore \, n=\frac{2}{7}=0.2857$