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Homework Help: Net Power Transfer by Radiation

  1. Jun 15, 2011 #1
    1. The problem statement, all variables and given/known data

    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.

    2. Relevant equations
    [itex]\Delta[/itex]Irad=[itex]\epsilon[/itex][itex]\sigma[/itex]T4 (Stefan-Boltzman Law)

    3. The attempt at a solution
    Temperature difference is 33-24=9 C
  2. jcsd
  3. Jun 15, 2011 #2


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    It probably would be nice to show a few more units in your calculations.
  4. Jun 15, 2011 #3
    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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