Given, T1,p1δλ1 be the initial temperature, pressure E mean free path i.e. T1=300K,p1=600 torr, λ1=10−7m and T2,p2 are final temperature and pressure i.e. T2=400K,p2=200 torr, λ2 be the final mean free path. As we know that, λ=
kT
√2πd2⋅p
where, d is diameter of molecule, p is pressure and k is Boltzmann constant, i.e. 1.38×10−23kg−m2s−1K−1 ∴λ∝