A 1.2 m high, 2 m wide glass window, 6 mm thick, k = 0.78 W/m·K, ε = 0.9. The room and the facing walls are at 25 °C and the inner glass surface is at 5 °C; outdoors −5 °C. Determine (a) the convection coefficient on the inner surface, (b) the total heat transfer through the window. Use the Churchill–Chu correlation Nu = {0.825 + 0.387 Ra^{1/6}/[1 + (0.492/Pr)^{9/16}]^{8/27}}^{2} with air properties at the film temperature.