A wall of a furnace is made up of inside layer of silica brick 120mm thick covered with a layer of magnetite brick 240mm thick. The temperature at the inside surface of silica brick wall and outside surface of magnetite brick wall are 725 OC and 110 OC respectively. The contact thermal resistance between the two walls at the interface is 0.00350 C/W per unit wall area. If thermal conduct ivies of silica and magnetite bricks are 1.7W/m OC and 5.8W/m 0C, Calculate. (i) The rate of heat loss per unit area of walls, and (ii) The temperature drop at the interface