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Q6. A furnace wall consists of 125 mm wide refractory brick and 125 mm wide insulating firebrick separated by an air gap. The outside wall is covered with a 12 mm thickness of plaster. The inner surface of the wall is at 1100°C and the room temperature is 25°C. The heat transfer coefficient from the outside wall surface to the air in the room is 17 W/m²K, and the resistant to heat flow of the air gap is 0.16K/W. The thermal conductivities of refractory brick, insulating firebrick, and the plaster are 1.6, 0.3, and 0.14 W/mK respectively. Calculate: (i) the rate of heat loss per unit area of wall surface; (08 marks) (ii) the temperature at each interface throughout the wall; (06 marks) (iii) the temperature at the outside surface of the wall. (06 marks)