Given, Pressure of the gas, p=1.01×105Pa Absolute temperature of gas, T=27∘C =27+273=300K Molecular diameter, d=0.3nm=0.3×10−9m Boltzmann constant, kB=1.38×10−23J∕K Mean free path, λ=
kBT
√2πd2p
....(i) Substituting the given values in Eq. (i), we get