Question 92 of 126

Two plates A and B have thermal conductivities $84W{m}^{-1}{K}^{-1}$ and $126W{m}^{-1}{K}^{-1}$ respectively. They have same surface area and same thickness. They are placed in contact along their surfaces. If the temperatures of the outer surfaces of A and B are kept at ${100}^{^{\circ}}C$ and ${0}^{^{\circ}}C$ respectively, then the temperature of the surface of contact in steady state is_____ $C^{\circ}$.