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Homework Help: Light Refracted through a Prism

  1. May 3, 2010 #1
    1. The problem statement, all variables and given/known data

    Light is incident along the normal to face AB of a glass prism of refractive index 1.66, as shown in the figure.

    [PLAIN]http://img175.imageshack.us/img175/6339/yffigure3336.jpg [Broken]

    Find [tex]\alpha[/tex]max, the largest value of the angle [tex]\alpha[/tex] such that no light is refracted out of the prism at face AC if the prism is immersed in air.

    2. Relevant equations
    I know I'm supposed to use Snells Law, but I really have no idea how to obtain the answer.

    3. The attempt at a solution

    I know that the incident angle is equal to 90 - [tex]\alpha[/tex] but thats all I know really.

    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. May 3, 2010 #2
    Yes the angle of incidence is 90-α
    I've drawn it in your diagram. (i)
    You now need to find what angle i needs to be in order that there is total internal reflection at the hypotenuse face of the prism.
    Using Snell's Law, do you know the criteria for total internal reflection?
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