In this problem you will consider the balance of thermal energy radiated and absorbed by a person. Assume that the person is wearing only a skimpy bathing suit of negligible area. As a rough approximation, the area of a human body may be considered to be that of the sides of a cylinder of length L=2.0m and circumference C=0.8m. For the Stefan-Boltzmann constant use σ=5.67×10−8W/m2/K4. Part A If the surface temperature of the skin is taken to be T_body=30∘C, how much thermal power P_rb does the body described in the introduction radiate? Take the emissivity to be e=0.6. Express the power radiated into the room by the body numerically, rounded to the nearest 10 W.
Part B Find P_net, the net power radiated by the person when in a room with temperature T_room=20∘C. Express the net radiated power numerically, to the nearest 10 W.