Why Does Light Reflect? - Unraveling the Mystery

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Discussion Overview

The discussion revolves around the phenomenon of light reflection, specifically exploring the underlying mechanisms at play when electromagnetic waves encounter shiny surfaces. Participants delve into atomic interactions, interface processes, and the application of boundary conditions in electromagnetic theory.

Discussion Character

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

Main Points Raised

  • Tom H questions the fundamental reason why light changes direction upon hitting a shiny surface, suggesting a possible atomic-level interaction.
  • One participant proposes that light reflects because it interacts with electrons in atoms, which absorb and then reemit light as they change energy levels.
  • Another participant expresses curiosity about how electrons "know" to emit photons at angles that obey the law of reflection, contrasting this with a simple bouncing ball analogy.
  • A different viewpoint emphasizes that the change in direction of light is not solely an atomic process but rather an interface phenomenon, suggesting that individual electrons do not scatter light in a specific direction.
  • Further clarification is sought regarding the term "interface process" and its implications for understanding reflection.
  • Another participant discusses applying boundary conditions for electromagnetic waves in conductors, indicating that the reflected wave can be derived from the electric and magnetic constants of the material and the wave equation.

Areas of Agreement / Disagreement

Participants express differing views on the mechanisms of light reflection, with some focusing on atomic interactions and others emphasizing interface processes. The discussion remains unresolved, with multiple competing perspectives presented.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about atomic interactions and the definitions of interface processes. The mathematical steps involved in deriving the law of reflection based on electromagnetic theory are not fully explored.

Tom H
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Why does light reflect?

I know that it does, and the rules and uses connected with this, but WHY does the em wave actually change direction on hitting a shiny surface? Is it at an atomic level?

Cheers

Tom H
 
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yes, the light hits the electrons in an atom, the light is absorbed then reammited by the electro as it changes energy level. :D so it looks like it has been reflected
 
nickthrop101 said:
yes, the light hits the electrons in an atom, the light is absorbed then reammited by the electro as it changes energy level. :D so it looks like it has been reflected

But, but... how does the electron "know" to emit the photon such that the angle of reflection exactly equals the angle of incidence? I can picture this happening if the photon simply bounced off the mirror like a ball, but this is evidently not the case. Hmmm...
 
The fact that light changes direction is not an individual atomic or electronic process but an interface process.
The individual electrons in atoms do not scatter light in a specific direction, obeying the law of reflection.
 
nasu said:
The fact that light changes direction is not an individual atomic or electronic process but an interface process.
The individual electrons in atoms do not scatter light in a specific direction, obeying the law of reflection.

Thanks, but could you explain what you mean by an "interface process."
 
When you look at an EM wave coming into contact with a conductor .
And you apply the boundary conditions for discontinuities in the electric and magnetic fields and the magnetic and electric constants of the material . you find that you get zero transmitted and the reflected wave is equal to minus the transmitted wave.

http://farside.ph.utexas.edu/teaching/315/Waves/node49.html
This site talks about EM wave propagation in conductors .
And shows that almost all is reflected and some is absorbed .
And i think you can derive the law of reflection based on the electric and magnetic constants of the material and the wave equation.
 
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