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Right-angle prisms

  1. Dec 9, 2006 #1
    i understand that when a ray of light enters a non-hypotenuse side of a right-angle prism at the perpendicular angle (90*) , it is reflected off the interior of the hypotenuse at a 90* angle, exiting out the other non-hypotenuse side

    how would light travel through a right angle prism if: the light entered a non-hypotenuse side of the prism at a non-perpendicular angle??

  2. jcsd
  3. Dec 9, 2006 #2


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    Staff: Mentor

    It refracts as it enters the prism and may or may not be totally internally reflected at the hypotenuse, depending on the angle with which it arrives at the hypotenuse. If it's not totally reflected, some will be refracted through the hypotenuse side and some will be reflected. The reflected ray emerges through one of the other sides. The details depend on the original incoming angle, and can be calculated by using Snell's Law and a bit of geometry at the refraction points.
  4. Dec 9, 2006 #3
    oh rite.. snell's law... ok, thanks.
  5. Dec 10, 2006 #4
    please confirm these diagrams of me!

    i understand that the critical angle of a specific glass prism may not be exactly 45*... but i know it will be similar to that.

    also, i understand that refraction will occur at incident angles less than 45*... but reflection also occurs as well right??

    Thus said, I would greatly appreciate if someone could confirm these two diagrams for me.

    - they are based on a right angle glass prism with critical angle 45*
    - the incident & reflected angles are measured from the hypotenuse to the respective rays.


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