the thermal conductivity of a door with a thickness of 8 mm is 0.78 W/M degrees celsius. the door measures 1500mm width and 800mm in height. if the indoor temperature is stays constant at 20 degrees celsius and the outside temperature is -10 degrees celsius , calculate the steady rate of heat transfer through the door and the temperature of its inner surface throughout the day. the heat transfer coefficient of the inner surface is 10 W/m^2 degrees celsius and 40 W/m^2 degrees celsius for the outer surface. consider the thermal conductivity to be constant and the heat transfer through the door to be steady and one dimensional