# Where does light get reflected on a conductor?

• Thierry12
In summary, the conversation discusses skin depth and how it affects the reflection of electromagnetic waves. The speaker asks about the location of reflection, whether it occurs at the border between air and metal or inside the conductor. The other person mentions Snell's Law and the Fresnel Reflection Coefficients as ways to determine how waves reflect. They also mention that reflection always occurs except in certain cases. The speaker recommends reviewing the theory of reflection and refraction in different sources and states that both the E and H components of an electromagnetic wave need to be matched at the boundary for proper reflection. They also mention their personal preference for a different source on the subject.
Thierry12
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

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.

## 1. What is a conductor and how does it relate to reflection?

A conductor is a material that allows the flow of electrical current. In the context of reflection, a conductor is important because it plays a role in determining the strength and direction of reflected electromagnetic waves.

## 2. How does a conductor affect the reflection of light?

A conductor has a high amount of free electrons that can easily move in response to an external electric field. When light waves hit a conductor, these free electrons oscillate and create an electromagnetic field that opposes the incident light wave. This results in a decrease in the intensity of the reflected light.

## 3. What is the skin effect and how does it impact reflection on a conductor?

The skin effect is a phenomenon where the current in a conductor tends to flow near the surface rather than through the entire cross-section. This is due to the resistance of the conductor increasing with frequency. In terms of reflection, the skin effect can cause a decrease in the amount of reflected energy as the higher frequency waves tend to be absorbed by the conductor instead of being reflected.

## 4. How does the thickness of a conductor affect the reflection of light?

The thickness of a conductor can have a significant impact on the reflection of light. As the thickness increases, the number of free electrons available to oppose the incident light also increases, resulting in a stronger reflection. However, there is a point where the thickness becomes too great and the light begins to penetrate through the conductor, resulting in a decrease in reflection.

## 5. Can a conductor change the polarization of reflected light?

Yes, a conductor can change the polarization of reflected light. This is due to the fact that when light reflects off a conductor, it becomes partially polarized in the direction of the reflected wave. This change in polarization can be used in applications such as polarizing filters and anti-glare coatings.

• Classical Physics
Replies
15
Views
509
• Other Physics Topics
Replies
7
Views
6K
• Classical Physics
Replies
4
Views
1K
• Optics
Replies
4
Views
677
• Quantum Physics
Replies
14
Views
2K
• Electromagnetism
Replies
4
Views
2K
• Special and General Relativity
Replies
51
Views
3K
• Optics
Replies
26
Views
4K
• Quantum Physics
Replies
46
Views
2K
• Classical Physics
Replies
4
Views
4K