One mole of a monoatomic gas is mixed with three moles of a diatomic gas. The molecular specific heat of mixture at constant volume is (α^2)/4 R J /…

One mole of a monoatomic gas is mixed with three moles of a diatomic gas. The molecular specific heat of mixture at constant volume is $\displaystyle \frac{\alpha^2}{4} \mathrm{R} \mathrm{J} / \mathrm{mol} \mathrm{K}$; then the value of $\displaystyle \alpha$ will be \_\_\_\_. (Assume that the given diatomic gas has no vibrational mode).