Question

When a heat of Q is supplied to one mole of a monatomic gas $(\gamma =5/3)$, the molar heat capacity of the gas at constant volume is

• A. $\frac{3R}{4}$
• B. $\frac{5R}{4}$
• C. $\frac{7R}{4}$
• D. $\frac{3R}{2}$

Answer 1

The correct option is D $\frac{3R}{2}$

Given $\gamma =5/3$

i.e $\frac{C_p}{C_v}=\frac{5}{3}$
and $C_p-C_v=R$

$\therefore \frac{C_v+R}{C_v}=\frac{5}{3}$
$1+\frac{R}{C_v}=\frac{5}{3}$

$C_v=\frac{3R}{2}$
Option D.