Reflection of Light on Mirrors: Why & How?

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Discussion Overview

The discussion centers around the mechanisms of light reflection on mirrors, exploring both the classical and atomic perspectives. Participants inquire about the principles behind light behaving similarly to a ball's velocity vector upon reflection and seek to understand the atomic interactions involved in this process.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions why light reflects off mirrors in a manner analogous to a ball's velocity vector, seeking atomic-level explanations for photon interactions with atoms.
  • Another participant mentions the corpuscular theory and speculates that electron excitation may occur in a specific plane or line, though they express uncertainty.
  • A participant reiterates their initial question about the atomic processes involved in light reflection, indicating a desire for deeper understanding.
  • One participant notes the scale difference between optical photons and atoms, suggesting that photons excite regions of solids rather than individual atoms.
  • Another participant describes specular reflection in metals, explaining that it involves collective oscillations of electrons in the conduction band, likening their behavior to dipole antennas acting in unison.

Areas of Agreement / Disagreement

Participants express varying degrees of understanding and uncertainty regarding the atomic mechanisms of light reflection. There is no consensus on the specific processes involved, and multiple viewpoints are presented without resolution.

Contextual Notes

Participants reference different theories and models, including corpuscular theory and collective electron behavior, but do not resolve the underlying assumptions or complexities involved in the reflection process.

nhmllr
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I understand why a ball's velocity vector is reflected across the line normal to the wall when it hits the wall. Why does this happen with light and a mirror? What is happening atomically for an atom to take in a photon and spit it out across the normal line?
 
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(I did post this in the Classical Physics section a few days ago, but I got no helpful replies and figured this would be a better forum.)

I understand why a ball's velocity vector is reflected across the line normal to the wall when it hits the wall. Why does this happen with light and a mirror? Intuitively it makes sense, but what is happening atomically for an atom to take in a photon and spit it out across the normal line?
 
Last edited:
Ohh...I remember something talking about this but I'll have to do some searching...I don't remember if it was in a book I have or on the internet somewhere. I'll see if I can get back to you.
 
Remember that an optical photon has a wavelength of hundreds of nanometers, while an atom is much smaller than this. The photon excites a region of the solid, not just an individual atom.

Specular reflection, in which Snell's law is obeyed, takes place in metals, where some of the electrons pass freely from one atom to another in what is known as the conduction band. The incoming photon excites a collective oscillation of these electrons. The effect of their motion is very similar to the usual simplified picture, of electrons acting as little dipole antennas all in phase.
 

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