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Wave Refraction

  1. Jun 4, 2008 #1
    Why does a wave refract as it enters a denser medium?
    i thought a wave was a photon and so i dont understand how a particle can be slowed down on one side before the other, enough that it changes direction by that much, would it not just move between the atoms? as most of the atom is just empty?
    Are photons effected by polarity? (eg. magnet)
  2. jcsd
  3. Jun 4, 2008 #2


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    What is "slowed" down is not the photon, but the group velocity of the wave. Since a "wave" has a wavefront, the varying instant that different parts of the wavefront hits the boundary is what causes the direction of the wave to change.

    Read the FAQ to know how photons are affected in a solid medium.

  4. Jun 4, 2008 #3


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    It is actually the wave velocity that equals c/n.
  5. Jun 4, 2008 #4
    Good question. The wave model of light is usually used to describe refraction, using a concept known as 'Huygen's principle'. But as to what physically causes the wavefront to slow in an optically denser material, I don't know.
  6. Jun 4, 2008 #5

    Andy Resnick

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    In terms of waves, the energy (frequency) is unchanged when moving across a material interface, but the momentum (wavlength) is changed.

    If you are asking for this picture to be explained in terms of particles, I don't know a clean way to do that.
  7. Jun 4, 2008 #6
    If the wave front hits the 'new' medium then where the atoms or particles are the wave will be slowed(or transfer energy) to the new mediums 'contents' (I mean molecules/atoms that make it up) some of the enrgy passes through these 'giant' gaps between the atoms where there is """"Nothing""" so some wave front continues, some wave front is stopped and some is transferred to this 'new' medium...???
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