Why do electromagnetic waves reflect

  • #1
716
180
I have seen the retarded potentials and what not, but what has always bothered me is why these field solutions reflect when they meet surfaces.
I have looked and looked, but there seem to be no analytical explanations for this, only empirical ones.
So my gripe is, since electromagnetic waves are nothing but EM fields, why do they reflect and diffract.
 

Answers and Replies

  • #2
vanhees71
Science Advisor
Insights Author
Gold Member
2021 Award
19,480
10,245
The theoretical explanation within classical Maxwell theory is that the fields must fulfill boundary conditions at the surface where two media join each other. From this you get, e.g., the laws of refraction and reflection in transparent media (dielectrics). This is treated in textbooks on electrodynamics and/or optics. Look for "Fresnel formulae".
 
  • #4
jtbell
Mentor
15,844
4,303
Look for "Fresnel formulae".

Or "Fresnel equations". A Google search for that term gives many hits. Some include derivations from Maxwell's equations.
 
  • #5
72
1
Doesn't anyone want to ...(oh never mind)...
 
  • #6
morrobay
Gold Member
817
427
Or "Fresnel equations". A Google search for that term gives many hits. Some include derivations from Maxwell's equations.

Fresnel's Laws apply to transparent materials. What about reflection from opaque objects ?
In post #3 above I reference a post by Antiphon. How would this classical explanation apply
or be modified for reflection from opaque object : Incidence = Absorbed+Reflected
 
Last edited:
  • #7
1,024
32
reflection from a surface or refraction has it's basis in the material itself.it is related to the plasma frequency of the metal.if the light which falls on a surface has frequency greater than plasma frequency will be transmitted but lower will be reflected.these things belong to solid state physics.you can see, kittel for it and also feynman lectures vol.2(last 1/4 of book).Also here is a link http://en.wikipedia.org/wiki/Plasmon
 

Related Threads on Why do electromagnetic waves reflect

  • Last Post
Replies
3
Views
949
Replies
35
Views
3K
  • Last Post
Replies
11
Views
3K
Replies
4
Views
901
Replies
6
Views
15K
Replies
2
Views
2K
Replies
31
Views
3K
Replies
1
Views
2K
Top