Blackbody radiation, de Broglie equation, and lightwaves to be shifted left I'm having a hard time

zuzogiecwu

zuzogiecwu

Answered question

2022-05-13

Blackbody radiation, de Broglie equation, and lightwaves to be shifted left
I'm having a hard time figuring this out.
1.Say we heated a lead ball to 1,000 Kelvin. Not all of the particles are at the exact same temperature--some parts are a little hotter, some are a little cooler. But for now, let’s assume that it follows a normal distribution that is centered at 1,000K.
2.The heat (or movement of the molecules) causes it to emit light.
3.Because the light photons have to be discrete (you can't have a 1/2 photon), this causes the observed light wavelengths to be shifted left.
4.This means we observe more red light than we might otherwise expect.
5.This is a long wind up to my specific question--does a particle vibrating at a specific frequency emit light at the same frequency? (i.e. a particle vibrating at 4.3 MhZ emits light at 4.3 Mhz). Because it seems like the whole thing hinges on that.
I mention this because I asked a physics teacher this, and he said, “No, the particles emit light following the de Broglie equation.” This would mean that the light emitted ignores the frequency and instead is based solely on its momentum. But, if this were true, then I would assume it would emit light in a standard distribution of frequencies as opposed to the left-skewed distribution that is actually observed.
Any help on this would be greatly appreciated!

Answer & Explanation

Corinne Choi

Corinne Choi

Beginner2022-05-14Added 15 answers

Your point three
"Because the light photons have to be discrete (you can't have a 1/2 photon), this causes the observed light wavelengths to be shifted left."
is incorrect. What is quantized is not what energies that can be emitted (those are continuous and correspond to frequency), but the amount of energy emitted at any particular frequency.
That is there is no rule that says you can emit light with photon energies of E or E + ϵ or $$E + 2\epsilon,or E + 3\epsilon$ and so on.
But there is a rule that says if you are emitting light with a frequency that corresponds to energy E or out unit then you can emit E or 2 E or 3 E, etc. in that frequency. You can still emit π 4 E, but it happens by emitting a different frequency.
The cause for the shape of the blackbody spectrum is the thermo-statistics of such quantized emissions.

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