A gas consisting of rigid diatomic molecules (degrees of freedom r = 5) under standard conditions `(P_(0) = 10^(5)` Pa and `T_(0) = 273 K`) was compressed adiabatically `eta = 5` times. Find the mean kinetic energy of a rotating molecule in the final state.

Explanation

Under compression, the temperature will rise
`TV^(gamma - 1) = constant, TV^(2//i) = constant`
or, `T(eta^-1 V_0)^(2//i) = T_0 V_0^(2//i)` or, `T' =eta^(+ 2//i) T_0`
So mean kinetic energy of rotation per molecule in the compressed state
=`1kT = kT_0 eta^(2//i) = 0.72 xx 10^-20 J`.