What is the net power that a person with surface area of 1.20 m² radiates if his emissivity is 0.895,his skin temperature is 27°C,and he is in a room that is at a temperature of 17°C? (σ = 5.67 × 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

We can use the Stefan-Boltzmann law to calculate the net power radiated by the person:
P = εσA(Ts^4 - Ta^4)
where ε is the emissivity, σ is the Stefan-Boltzmann constant, A is the surface area, Ts is the skin temperature, and Ta is the room temperature.

Plugging in the given values, we get:
P = 0.895 * 5.67x10^-8 * 1.20 * (300^4 - 290^4)

Simplifying, we get:
P ≈ 62.6 W

Therefore, the best choice is B, as it matches our calculation.

What Is the Net Power That a Person with Surface