Q2. A layer of pulverized cork 6 inch thick is used as a layer of thermal insulation in a flat wall. The temperature of the cold side of cork is 40 F and that of warm side is 180 F. The thermal conductivity of the cork at 32 Fis 0.021 Btu/ft-h-"F and at 200 F is 0.032. The area of the wall is 25 ft? What is the rate of heat flow through the wall in Btu/hr