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Homework Help: Wave Phenomena - Refraction

  1. Nov 26, 2011 #1

    I am learning about refraction and the million ways in which Snell's Law is presented to me is making me confused...

    So, I understand that:

    sin i / sin r, will give me the ratio of speeds ci/cr and λir

    However, I can't understand this form of:

    n1sin i = n2 sin r

    How does it drop out?

    Peter G.
  2. jcsd
  3. Nov 26, 2011 #2

    Doc Al

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    Staff: Mentor

    Don't forget the meaning of the index of refraction:
    n = c/v (where c = speed of light in a vacuum and v = speed of light in the media)

    In your notation:
    c1 = c/n1
    c2 = c/n2
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