Where does light get reflected on a conductor?

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Discussion Overview

The discussion revolves around the reflection of light on a conductor, specifically addressing the mechanics of reflection at the boundary between air and metal, and the implications of skin depth on this phenomenon. Participants explore theoretical aspects, including the conditions under which reflection occurs and the nature of the reflected wave.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions whether reflection occurs at the boundary between air and metal or within the conductor itself, noting the apparent coherence of the reflected light beam.
  • Another participant references Snell's Law and the Fresnel Reflection Coefficients, suggesting that reflection is generally present unless specific conditions, such as matching material properties or polarization at the Brewster Angle, are met.
  • A different participant recommends reviewing classical electrodynamics texts for a deeper understanding of the reflection and refraction of electromagnetic waves, emphasizing the need for matching both electric and magnetic components at the boundary.
  • One participant expresses a preference for Griffiths' text over Jackson's for introductory material on plane wave reflection, indicating a subjective view on the quality of the sources.

Areas of Agreement / Disagreement

Participants express differing opinions on the appropriateness of various textbooks for understanding the topic, and there is no consensus on the specific mechanics of reflection at the boundary versus within the conductor.

Contextual Notes

Participants reference specific conditions for reflection, such as polarization and material properties, but do not fully resolve the implications of skin depth or the exact location of reflection within the conductor.

Thierry12
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Hi, skin depth tells us that an electromagnetic wave is attenuated but when is it reflected?
When i aim light on a mirror its clearly reflected. My question is if its at the border ( right when it goes from air to metal) or at some place inside the conductor (if the latter, then how is a reflected light almost a perfect beam?)

ty
 
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Snell's Law or the Fresnel Reflection Coefficients will show you how the waves reflect. For the most part though, you always have a reflected wave. The only times you do not have reflection is when the medium you are transitioning to has the same material properties and when you have the proper polarization of light striking the surface at what is known as the "Brewster Angle."
 
You should review the theory of reflection and refraction of plane electromagnetic waves and wave propagation in Jackson "Classical Electrodynamics" Second Edition pgs 269-292, or in Slater and Frank "Electromagnetism" Chapter X. In general, both the E and H components of an electromagnetic wave need to be separately matched at the boundary, usually requiring both a reflected and refracted component. This matching depends on the wave polarization.
 
I hate Jackson as an introductory source. I believe Griffiths' Introduction to Classical Electrodynamics will have plane wave reflection. I curse the day that I left that book back in the States.
 

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