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Homework Help: Thermal Radiation

  1. Jun 11, 2009 #1
    1. The problem statement, all variables and given/known data

    Consider the following three solid object all made of the same material;
    1) Cube of edge length r
    2) Sphere of radius r
    3) Hemisphere of radius r

    All object are maintained at a temperature 350K in an envorinment at temperature 300K. Rank the objects according to the net rate at which they exchange thermal radiation with the environment. Justify for full marks.

    2. Relevant equations

    3. The attempt at a solution

    Im not sure whether to list them simply in order of surface area or not??? Is there something else I should be considering? Cheers.
  2. jcsd
  3. Jun 11, 2009 #2


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    Homework Helper

    So if you list them in terms of surface area, why would you justify it to be in that order?

    Even though you have the correct idea, you should know this formula [itex]E=A \sigma T^4[/itex] (Stefan's law of black body radiation)
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