Uncovering the Mystery of Photon Wavelength Reflection and Momentum Transfer"

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Discussion Overview

The discussion revolves around the behavior of photons during reflection, specifically whether their wavelength changes as a result of momentum transfer to an object upon reflection. Participants explore the implications of photon momentum and energy transfer in both theoretical and practical contexts.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions whether photons become longer in wavelength after reflecting off an object, suggesting that momentum transfer would imply a loss of energy and thus a longer wavelength.
  • Another participant agrees with the initial inquiry but suggests that the practical effects of such a phenomenon may be negligible, indicating that it is not commonly discussed.
  • A third participant introduces Compton scattering as a related phenomenon, implying that it involves similar principles of photon interaction.
  • A fourth participant clarifies that while wavelength changes are significant in cases like Compton scattering involving elementary particles, they may not be as noticeable when considering macroscopic objects.

Areas of Agreement / Disagreement

Participants express varying views on the significance of wavelength changes upon reflection, with some acknowledging the theoretical possibility while others emphasize the practical limitations and context of the discussion. No consensus is reached regarding the extent of the effect in different scenarios.

Contextual Notes

Limitations include the dependence on the scale of interaction (macroscopic vs. microscopic) and the potential oversight of practical calculations that could clarify the discussion.

Neo_Anderson
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...become longer in its wavelength after it reflects off something? After all, photons do have momentum; I'd at least expect photons to transfer some of its energy to the object as it reflects off it, causing them to become less energetic, hence lengthening its wavelength.
I'm mistaken, I know, but how so?...
 
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You're not mistaken. However, try calculating how big this effect would be in a practical situation, and you'll probably get an idea of why people don't talk about it much.
 
Compton scattering is a very analogous phenomenon to the one you are describing.
 
Sure, if a photon scatters off an individual electron or other elementary particle (Compton scattering is an example), or probably even an atom, the change in wavelength is noticeable. I had the impression Neo was thinking of macroscopic objects (maybe I was mistaken).
 

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