Net Power Transfer by Radiation

AI Thread Summary
The problem involves calculating the net power transfer by radiation from a person with a skin temperature of 33°C and an emissivity of 0.9 in a room at 24°C, with a body area of 1.8 m². Using the Stefan-Boltzmann Law, the temperature difference is established as 9°C. The radiation intensity is calculated as 3.34 x 10^-4 W/m², leading to a total power transfer of approximately 6.03 x 10^-4 W. There is some confusion regarding the necessity of converting temperature differences to Kelvin, but it is clarified that the difference remains the same in both scales. The calculations should consistently include units for clarity.
ethanabaker1
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Homework Statement



A person with a skin temperature of 33 C and an emissivity of .9 is in a room at 24 C. What is the net power transfer by radiation. Let the area of the body be 1.8 m2.

Homework Equations


I=\frac{P}{A}
\DeltaIrad=\epsilon\sigmaT4 (Stefan-Boltzman Law)


The Attempt at a Solution


Temperature difference is 33-24=9 C
Irad=(.9)(5.67x10-8)(94)
Irad=3.34x10-4
IradA=Power
(3.34x10-4)(1.8)=6.03x10-4
 
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It probably would be nice to show a few more units in your calculations.
 
Well, power should have units of Watts. Emissivity has no units, and I know the Boltzman constant is Wm-2K-4, so I wasn't sure if that means I should convert the temperature difference to Kelvin or not. I left it because both Kelvin and Celsius should have the same temperature difference. But I don't even know if that solution is reasonable.
 

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