Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Refraction and Prisms

  1. Sep 6, 2015 #1
    upload_2015-9-6_17-14-32.png

    That is a page from my textbook. The book mentions that the angle of incidence on the right side when added with the angle of the refraction equals 60 degrees. Why is that?
     
  2. jcsd
  3. Sep 6, 2015 #2

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    Consider the triangle formed by the light ray in the prism and the two prism borders. The sum of the interior angles is 180°, and one angle is 60°. Everything else follows from geometry with the right angles there.
     
  4. Sep 6, 2015 #3
    Which triangle? If you mean the one formed by the refracted ray, it is not a right angle triangle.
     
  5. Sep 7, 2015 #4

    blue_leaf77

    User Avatar
    Science Advisor
    Homework Helper

    Triangle ABC:
    $$
    \angle A + \angle B + \angle C = 180^0
    $$
    Or triangle formed by B, C, and the prism's apex.
     

    Attached Files:

    Last edited: Sep 7, 2015
  6. Sep 7, 2015 #5

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    Another way to look at it. The very top triangle has one angle of 60°. The other two angles are 90- i and 90-r etc. etc.....
     
  7. Sep 7, 2015 #6

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    That is the triangle I meant.
    And the sum of those three angles is 180 degrees.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Refraction and Prisms
  1. Light and prisms . (Replies: 2)

  2. Rainbows and prisms (Replies: 2)

  3. Prism Experiment (Replies: 1)

  4. Dichromatic(?) prisms (Replies: 1)

Loading...