Why photons reflect off glass?

In summary, the conversation discusses the behavior of photons as they pass through different substances, such as glass and water. It is explained that the reason for this behavior is due to the energy levels of electrons in the substance, where some photons are able to excite the electrons while others are not. The idea of atomic transitions is corrected, and it is clarified that this phenomenon is not related to general relativity. It is suggested to understand the classical description of light before delving into the quantum field theory explanation. A book recommendation is also provided for further understanding.
  • #1
Christian Grey
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Why photon reflects and refracts through glass? Some photons pass through glass and some reflects.I know this is due to energy levels of electrons of glass, an incoming photon is unable to excite the electron to a different energy orbit.

But I want to know, if an incoming photon is unable to excite an electron, then why not all the photons pass through glass? i.e. photons should not reflect off glass, all the photons should pass through glass.
 
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  • #2
You might want to start by reading this, especially in correcting your idea about atomic transition, and how solids are different than atoms.

https://www.physicsforums.com/threads/do-photons-move-slower-in-a-solid-medium.511177/ [Broken]

Zz.
 
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  • #3
ZapperZ said:
You might want to start by reading this, especially in correcting your idea about atomic transition, and how solids are different than atoms.

https://www.physicsforums.com/threads/do-photons-move-slower-in-a-solid-medium.511177/ [Broken]

Zz.

That doesn't explain what I'm looking for.
 
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  • #4
Christian Grey said:
That doesn't explain what I'm looking for.

I said that it is a start, because it should dispel the idea that this is an "atomic transition" phenomenon, and that you need to be aware of a collective behavior when a solid is formed.

A "reflection" can be caused by a number of phenomena. The simplest of which is a photon scattering off the lattice.

Zz.
 
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  • #5
<<Moderator note: Originally posted as duplicate thread. Removed content identical to the first post.>>

Is this due to atoms of different substances like water,glass or wood etc curve spacetime differently and thus it influences how photons interact with matter? i.e. some photons reflect and some refract.
 
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  • #6
Christian Grey said:
But I want to know, if an incoming photon is unable to excite an electron, then why not all the photons pass through glass? i.e. photons should not reflect off glass, all the photons should pass through glass.

This is classical physics, so you might want to work on understanding the classical description before worrying about how the description in terms of quantum field theory reduces to it in the classical limit. If you need help with that, the classical physics forum would be the place to ask.

Christian Grey said:
Is this due to atoms of different substances like water,glass or wood etc curve spacetime differently and thus it influences how photons interact with matter? i.e. some photons reflect and some refract.

No, this has nothing to do with general relativity. Rays of light follow geodesics when there is no other interaction besides gravity. Here gravity is negligible, and the dominant interaction is electromagnetic.
 
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  • #7
bcrowell said:
This is classical physics, so you might want to work on understanding the classical description before worrying about how the description in terms of quantum field theory reduces to it in the classical limit.
This is a common and extensive problem among laymen who read their share of popular science. The message conveyed seems to be that light are photons, which are small balls of light that should behave similar to how balls behave on a classical level. Nowhere in popular science is it mentioned that gauge theories are about as complicated as it gets when it comes to quantisation and that many of the properties of light is easiest explained in the classical limit.
 
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  • #8
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1. What is the mechanism behind photons reflecting off glass?

Photons reflect off glass due to the process of specular reflection, which involves the interaction of light with the smooth surface of glass. When light hits the surface, some photons are absorbed while others are reflected in a specific direction, resulting in the reflection of light.

2. Why do photons reflect off glass and not other materials?

Glass is a transparent material, meaning that it allows most of the light to pass through it. However, the smooth surface of glass provides a perfect surface for specular reflection, resulting in the majority of photons being reflected rather than passing through.

3. How does the angle of incidence affect the reflection of photons off glass?

The angle of incidence refers to the angle at which light hits the surface of glass. The law of reflection states that the angle of incidence is equal to the angle of reflection, meaning that the direction of the reflected photons is dependent on the angle at which the light hits the glass surface.

4. Can photons reflect off glass at different wavelengths?

Yes, photons can reflect off glass at different wavelengths. This is because the interaction between light and glass is dependent on the frequency of the light, which determines how the photons will be absorbed and reflected by the glass surface.

5. Is the reflection of photons off glass affected by the thickness or type of glass?

Yes, the thickness and type of glass can affect the reflection of photons. Thicker or tinted glass may absorb more light, resulting in a lower amount of reflected photons. Additionally, different types of glass may have different properties that can alter the reflection of photons, such as a rougher or smoother surface.

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