$\frac{\Delta U}{\Delta Q}=\frac{n C_V \Delta T}{n C_P \Delta T}=\frac{C_V}{C_P}=\frac{1}{\gamma}$

$\left(\frac{\Delta U}{\Delta Q}\right)_{\text {mono }}=\frac{1}{\gamma_{\text {mono }}}=\frac{3}{5}$

$\left(\frac{\Delta U}{\Delta Q}\right)_{\text {dia }}=\frac{1}{\gamma_{\text {dia }}}=\frac{5}{7}$

$\left(\frac{\Delta U}{\Delta Q}\right)_{\text {tria }}=\frac{1}{\gamma_{\text {tria }}}=\frac{3}{4}$

Fractional energy used to change internal energy is maximum in Triatomic gas.