Question

If the ratio of specific heat of gas at constant pressure to that at constant volume is $\gamma$, the change in internal energy of a gas, when the volume changes from $V$ to $2V$ at constant pressure $P$ is

• A. $\frac{R}{(\gamma -1)}$
• B. $PV$
• C. $\frac{PV}{(\gamma -1)}$
• D. $\frac{\gamma PV}{(\gamma -1)}$

Answer 1

The correct option is C $\frac{PV}{(\gamma -1)}$

Chane in internal energy is
$△U=n{C}_v△T\Delta U=n\frac{R}{\gamma -1}(T_f-T_i)$

$\Delta U=\frac{P_f{V}_f-P_i{V}_i}{\gamma -1}=\frac{PV}{\gamma -1}$