1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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
    I=[itex]\frac{P}{A}[/itex]
    [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
    Irad=(.9)(5.67x10-8)(94)
    Irad=3.34x10-4
    IradA=Power
    (3.34x10-4)(1.8)=6.03x10-4
     
  2. jcsd
  3. Jun 15, 2011 #2

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    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.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Net Power Transfer by Radiation
Loading...