Is radiation from non-black bodies a different color at the same temperature?

  • #1

Summary:

Does not-black body shows different colors for the same temperature?

Main Question or Discussion Point

Hello, I've searched a bit about about the thermal radiation behavior of non-black body and I'm confused.
I've read that the color is dependent only on the temperature so every thing display the same color as a black body.
But at the same time I've read that materials don't always follow the spectrum of a black body.

I've also read that composition plays no role in the color output however the blue flame of a blowing torch is due to the chemicals in the gas and not that it is as hot as a blue star.

I'm confused :frown:

Surely I'm not the only one asking that but I did not found a satisfying answer ( or did not use the wight words for searching )

Thanks for the help and nice week!
 

Answers and Replies

  • #2
838
372
Non-black bodies do not necessarily emit the same color or spectral intensity as a black body.
However the amount of every wavelength in every direction of thermal radiation emitted by a body at temperature T, black or not, is equal to the corresponding amount that the body absorbs.
If the body emits a constant (over wavelength) fraction of the intensity of a perfect black it is usually called a gray body.
I believe wikipedia does a pretty good job on this subject.
 
  • #3
Thanks I think I got it.
 

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