[QUE/TH-12002] TH-PROBLEM

A box is divided into two equal parts by a non-conducting partition having a hole of diameter $D$. Initially, some Helium gas is preset on both sides at temperature $T_1$ K and $T_2$K, by heating the walls of the box.

(a) What is the steady state when $D\,>>\,L_1$ and $D\,>>\,L_2$ where $L_1$ and $L_2$ are mean free paths at temperature $T_1$ and $T_2$ respectively.

(b) What is the steady state when $D\,<<\,L_1$ and $D\,<<\,L_2$ where $L_1$ and $L_2$ are mean free paths at temperature $T_1$ and $T_2$ respectively.