Heat is lost through a plane wall steadily at a rate of 800 W. If the inner

Question:

Heat is lost through a plane wall steadily at a rate of 800 W. If the inner and outer surface temperatures of the wall are 20°C and 5°C, respectively, and the environment temperature is 0°C, the rate of energy destruction within the wall is
(a) 40 W
(b) 17,500 W
(c) 765 W
(d) 32,800 W
(e) 0 W