As a rough approximation, the human body may be considered to be a cylinder of length l=2.0m and circumference c=0.8m . (to simplify things, ignore the circular top and bottom of the cylinder, and just consider the cylindrical sides.) if the emissivity of skin is taken to be e=0.6 , and the surface temperature is taken to be t= 30 ∘ c , how much thermal power p does the human body radiate?

458.826 watts

Explanation:

According to Stefan-Boltzmann's Law, thermal energy emitted by a black body per second per unit area is directly proportional to the fourth power of the absolute temperature and is given by;

= σ

P = ?

A = l x c = 2 x 0.8 =

(Please ignore Armstrong symbol, I don't know how it appeared using the equation tool)

σ =

e = 0.6

T = = 303 K

P = σeTA

P = x 0.6 x x 1.6

P = 458.826 watts