Relation between photons and EM wave frequency

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Discussion Overview

The discussion revolves around the relationship between photons and electromagnetic (EM) wave frequency, exploring whether individual photons possess attributes that correlate with the frequency of the EM waves they comprise. Participants examine the implications of photon frequency on energy and momentum, as well as the distinctions between different colors of light, such as red and blue.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that photons composing blue light have a higher frequency, which implies higher momentum and energy compared to those composing red light.
  • Others express uncertainty about attributing frequency to individual photons, questioning how to differentiate between different quantities of photons with varying energies.
  • One participant mentions that multi-photon absorption could occur under certain conditions, suggesting that statistical differences could be observed in photon absorption processes.
  • There is a discussion about the photoelectric effect, with participants noting that it is frequency alone that determines electron emission, regardless of amplitude or wavelength.
  • Some participants argue that while wavelength and frequency are correlated, amplitude can vary independently, which leads to counterintuitive results in the context of the photoelectric effect.
  • Another participant asserts that a single photon does not possess amplitude, but rather that electromagnetic radiation has an amplitude that relates to the number of photons.

Areas of Agreement / Disagreement

Participants express differing views on the attribution of frequency to individual photons and the implications of amplitude in the context of the photoelectric effect. The discussion remains unresolved with multiple competing perspectives on these topics.

Contextual Notes

Participants reference the photoelectric effect and its dependence on frequency, but there are unresolved questions regarding the measurement and differentiation of photons based on energy and the role of amplitude.

humbleteleskop
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Do individual photons have some attributes which relate to EM wave frequency? In other words, is there any difference in photons composing a red and blue beam of light?
 
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Certainly, photons composing blue light have a higher frequency which means they have a higher momentum, and a higher energy.
 
Matterwave said:
Certainly, photons composing blue light have a higher frequency which means they have a higher momentum, and a higher energy.

I didn't think frequency could be attributed to individual photons.

How do we differentiate 1,000 photons each having energy E, from 2,000 photons having energy E/2? What would be the instrument or type of sensor that could tell that difference?
 
humbleteleskop said:
I didn't think frequency could be attributed to individual photons.

How do we differentiate 1,000 photons each having energy E, from 2,000 photons having energy E/2? What would be the instrument or type of sensor that could tell that difference?


If all of the photons hit at the same time, and in the same small area, you could get multi-photon absorption - 1,2,3, or more photons absorbed by each process. But the statistics will not be uniform, so you can tell; but this requires the conditions when non-linear optics is required.

The photo-electric effect (see Einstein, 1905: http://en.wikipedia.org/wiki/Photoelectric_effect) applies in most ordinary circumstances - and then the metal plate has no trouble telling the difference between photons with energy higher than the work function barrier, and those below.
 
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Interesting. Especially the part how neither amplitude nor wavelength are responsible for the effect, but frequency alone. Which doesn't really make sense to me as I understand all three are proportionally correlated, so I don't see how frequency can be independent of the other two in such way.
 
humbleteleskop said:
Interesting. Especially the part how neither amplitude nor wavelength are responsible for the effect, but frequency alone. Which doesn't really make sense to me as I understand all three are proportionally correlated, so I don't see how frequency can be independent of the other two in such way.

Wavelength and frequency are (of course) correlated, but amplitude can be varied independently. The surprising and counterintuitive thing about the the photoelectric effect is that it doesn't matter how much you dial up the amplitude and therefore how much energy is transferred to the target - you won't get any electron emission if the frequency is too low (equivalently, if the wavelength is too great).
 
Yes, I always thought that the wavelength was c/f. I don't think a single photon had an amplitude though.
 
Jilang said:
Yes, I always thought that the wavelength was c/f. I don't think a single photon had an amplitude though.

It doesn't. Electromagnetic radiation has an amplitude, and that determines (sort of) the number of photons.
 

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