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Homework Help: Angles of Light and Prisms

  1. Aug 5, 2014 #1
    1. The problem statement, all variables and given/known data

    Light is incident on a glass prism with an angle of incidence of 54°. The light enters on the left hand side of a triangular prism with base angles of 80° and apex angle of 20°. (The 54° ray of incidence enters from the south west side of the prism, directed towards the north east). Calculate all the angles as a ray of light travels through a prism. Assume that the prism is surrounded with air therefore n=1, also the n value of the prism is n=1.7.

    2. Relevant equations

    snell's law: n1sinΘ1=n2sinΘ2

    3. The attempt at a solution
    With the given information i drew the image and determined through snell's law that the first angle of refraction (Θ2) equals 28.4°... I don't understand how to find Θ3.
  2. jcsd
  3. Aug 5, 2014 #2

    Simon Bridge

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    Homework Helper

    You have to use you knowledge of triangles and angles to work out an incident angle to the second side.
    Since you have a sketch, you can continue the ray into the prism until it strikes the other side.
    The ray and the apex of the prism will make a triangle where you know two of the angles.
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