A room has a 4 mx 4 mx 10 cm concrete roof (K = 1.26 Wm C). At some instant, the temperature outside is 46C and that inside is 32C. (a) Neglecting convection, calculate the amount of heat flowing per second into the room through the roof. (b) Bricks (K= 0.65 Wm C) of thickness 7.5 cm are laid down on the roof. Calculate the new rate of heat flow under the same temperature conditions.