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Reflection of light

  1. Aug 12, 2007 #1
    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?


    Tom H
  2. jcsd
  3. Mar 13, 2011 #2
    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
  4. Mar 13, 2011 #3
    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...
  5. Mar 13, 2011 #4
    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.
  6. Mar 13, 2011 #5
    Thanks, but could you explain what you mean by an "interface process."
  7. Mar 14, 2011 #6
    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.

    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.
    Last edited: Mar 14, 2011
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