Maximum temperature under radiation

AI Thread Summary
The discussion centers on calculating the maximum equilibrium temperature of a metal under electromagnetic radiation, considering both the incoming radiation and the black body radiation that cools it. The key formula derived is p_0 = σAT^4, indicating that the temperature remains constant when the energy from external radiation is balanced by the energy lost through black body radiation. Participants emphasize the importance of accurately determining the net energy flow to find the equilibrium temperature. One user expresses a need to reconcile their results with existing publications. The conversation highlights the interplay between radiation absorption and emission in determining temperature.
abbasranjbar
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Hello everyone,
As you all know, the temperature of a metal increases under electromagnetic radiation. The metal also has a black body radiation which decreases its temperature. There is an equilibrium temperature which is the maximum temperature of the metal under the radiation. I am looking for formulas or publication that gives me this final temperature.

Thanks
 
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Hm, it seems you want to calculate the net energy flow with

dE_- = -p(T)\,dt = -\sigma\,A\,T^4\,dt

where p(T) is the integrated density from Stefan-Boltzmann, and from an external radiation source with

dE_+ = p_0\,dt

Then you are looking for

dE_- + dE_+ = 0

Correct?
 
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Yes, actually the equilibrium T of the material because of this net energy.
 
OK, you have

dE_+ + dE_- = 0
p_0\,dt - \sigma\,A\,T^4\,dt = 0
p_0 = \sigma\,A\,T^4

So the temperature is constant iff the black body radiation is balanced by radiation received from the external source.
 
Thank you Tom.
That makes sense. I checked it couple of times and my results were not match with the publications. I will check again to find the reason of the difference.

Cheers
 
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