The surface area of a person is $1.9 \, m^2$,their body temperature is $37 \, ^oC$,and the room temperature is $22 \, ^oC$. If the temperature of the skin is $28 \, ^oC$,find the rate of heat emission. The emissivity of the skin is $0.97$.

(C) The rate of energy emission $H$ from a body is given by the Stefan-Boltzmann law: $H = A e \sigma (T^4 - T_S^4)$.
Here,the surface area $A = 1.9 \, m^2$,emissivity $e = 0.97$,and Stefan-Boltzmann constant $\sigma = 5.67 \times 10^{-8} \, W/m^2K^4$.
The skin temperature $T = 273 + 28 = 301 \, K$.
The surrounding room temperature $T_S = 273 + 22 = 295 \, K$.
Substituting the values:
$H = 1.9 \times 0.97 \times 5.67 \times 10^{-8} \times [(301)^4 - (295)^4]$
$H = 10.44981 \times 10^{-8} \times [8208541201 - 7573350625]$
$H = 10.44981 \times 10^{-8} \times 635190576$
$H \approx 66.38 \, W$.
Thus,the rate of heat emission is approximately $66.4 \, W$.