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Homework Help: Incidences of refraction

  1. Jan 23, 2015 #1
    1. The problem statement, all variables and given/known data
    I am preparing for a test. I really need help with this is problem. I uploaded a picture for the figure.
    The figure below shows the path of a beam of light through several layers (n1 = 1.58, n2 = 1.39, n3 = 1.21 and n4 = 1.00) of different indices of refraction.

    If mimetex.gif = 29.1o, what is the angle, mimetex.gif , of the emerging beam?

    PART 2:
    What must the incident angle, mimetex.gif , be in order to have total internal reflection at the surface between the n3 = 1.21 medium and the n4 = 1.00 medium?

    2. Relevant equations

    We have to use Snell's Law: which is n1sin=n2sin

    3. The attempt at a solution

    FOR PART 1: This is what I did:
    I know N for 1 and 2. The angle is 29.1 as given. So....

    mimetex.gif sin^-1=(n1/n2*sin) sin^-1=(1.58/1.39*sin29.1). I get .662 which is off.

    For Part 2: I am clueless.

    Please guide me.

    Attached Files:

  2. jcsd
  3. Jan 23, 2015 #2

    rude man

    User Avatar
    Homework Helper
    Gold Member

    Your equation makes no sense to me. Try again? Start with Snell's law again, carefully.
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