What is the net power that a person loses through radiation if her surface area is 1.20 m², if her emissivity is 0.895, if her skin temperature is 300 K, and if she is in a room that is at a temperature of 17°C? The Stefan-Boltzmann constant is 5.670 × 10^-8 W/m² · K⁴. A) 60.3 W B) 62.6 W C) 65.7 W D) 68.4 W E) 64.8 W

Question

Quizplus · Accepted Answer

First, we need to convert the room temperature to Kelvin: 
17°C + 273.15 = 290.15 K

The net power lost through radiation can be calculated using the formula: 
P = εσA(T^4 - T_room^4)

where:
ε = emissivity = 0.895
σ = Stefan-Boltzmann constant = 5.670 × 10^-8 W/m^2K^4
A = surface area = 1.20 m^2
T = temperature in Kelvin = 300 K
T_room = room temperature in Kelvin = 290.15 K

Plugging in the values: 
P = 0.895 × 5.670 × 10^-8 × 1.20 × (300^4 - 290.15^4)
P = 62.6 W

Therefore, the net power lost through radiation is 62.6 W. Choice B is the best answer.

What Is the Net Power That a Person Loses Through