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Homework Help: Finding an objects surrounding temperature

  1. Mar 9, 2013 #1
    1. The problem statement, all variables and given/known data

    Hi, I have just started with physics and this is my first time posting on this forum, The question is very confusing. it asks:
    What is an objects surrounding temperature (T0) if we know the:
    T=303 K
    P (net radiated power gained)= 155 W

    See attachment, question 3(c)

    2. Relevant equations

    P=εσA(T^4-T0^4) or εσAT^4

    3. The attempt at a solution

    I have not made an attempt, the answer of the first equation requires both surrounding temperature (T0) and the temperature of the object (T) but the answer would be the rate at which an object radiates energy; in joules, not watts (from what I understand) but the other equation doesn't have the T0, so you can't use algebra to solve it.
    Please don't just type the answer, explain how you got it.


    Attached Files:

  2. jcsd
  3. Mar 9, 2013 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    You appear to have all the info needed to solve your equation for T0 using..


    where P is in Watts. One Watt = one Joule per second.

    P=εσAT^4 - εσAT0^4

    εσAT0^4 = εσAT^4 - P

    T0^4 = T^4 - P/εσA

    T0 = (T^4 - P/εσA)^-4

    T=303 K
    P (net radiated power gained) = 155 W = 155 J/S
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