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Homework Help: Heat radiation

  1. Jan 30, 2016 #1
    1. The problem statement, all variables and given/known data
    At what rate does a 0.1m cube of metal with emissivity e=0.75 radiate energy if it is at a temperature of 200C?

    2. Relevant equations

    H=AeσT^4, σ=5.67 x10^-8
    3. The attempt at a solution
    I found the area of the cute to be A=(0.1m)^2=0.01m, and the turned 200C into 473K, but when I type them all in I get 21.28W and the answer is 128W?
  2. jcsd
  3. Jan 30, 2016 #2


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    Staff: Mentor

    How many faces does a cube have?
  4. Jan 30, 2016 #3
    6.. thanks!
  5. Jan 30, 2016 #4


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    Staff Emeritus
    Science Advisor
    Homework Helper

    Also, (0.1 m)2 = 0.01 m2 Don't forget to square the units.
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