Question

The ratio of average translational kinetic energy to rotational kinetic energy of a diatomic molecule at temperature T is x/y.
then value of x+y is...........

Answer 1

For a diatomic molecule, the three translation direction contribute 1/2 kT per molecule, and for each molecule there are also two axes of rotation, contributing rotational kinetic energy in the amount of 1/2 kT each.
So total translational kinetic energy $=\left(3/2\right)kT$ & total rotational kinetic energy $=\left(2/2\right)kT$.
So, the ratio of average translational kinetic energy to rotational kinetic energy of a diatomic molecule at temperature T is (3/2).
So sum of ratio is 3+2 = 5