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Snell's Law and Refraction

  1. Mar 27, 2009 #1
    1. The problem statement, all variables and given/known data
    One method of determining the refractive index of a transparaent solid is to measure the critical angle when the solid is in air. It Ac is found to be 40.5 degrees, what is the index of refraction of the solid?

    2. Relevant equations

    3. The attempt at a solution

    where does the 40.5 go? what does "critical angle" mean?
  2. jcsd
  3. Mar 27, 2009 #2


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    Homework Helper

    the critical angle is the maximum angle such that the refracted angle is 90 degrees.

    Meaning that at i=c,r=90

    so that sin(r)/sin(i)=n => sin90/sinc=n

    for i>c, the light is reflected back into the medium and total internal reflection occurs.

    in your question the critical angle is 40.5 degrees.
  4. Mar 27, 2009 #3
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