The fire brick of Example 12.9 is used to construct the walls of a brick oven. The irradiation on the interior surface of the wall is G = 50,000 W/m2 and has a spectral distribution proportional to that of a black-body at 2000 K. The temperature of the gases adjacent to the inner wall of the oven is 500 K, and the convection heat transfer coefficient is 25 W/m2. Find the wall surface temperature if the heat loss through the wall is negligible. If the brick wall is 0.1 m thick and of thermal conductivity kb = 1.0 W/m ∙ K, and is insulated with a 0.1-m-thick layer of thermal conductivity k1 = 0.05 W/m ∙ K, what is the steady-state interior wall surface temperature if the temperature of the external surface of the insulation is 300 K?