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Homework Help: Refraction Problems

  1. Mar 29, 2004 #1
    problem 4.
    A ray of light traveling in air strikes a flat 2.00 cm tick block of glass (n=1.50) at an angle of 25.6 degrees with the normal.
    Trace the light ray through the glass, and find the angle of refraction for light passing from air to glass. Answer in degrees.
    Note: I don't know where to start.
    Problem 6.
    The angle of incidence and the angle of refraction for light going from air into a material with a higher index of refraction are 66.1 degrees and 42.2 degrees, respectively.
    What is the index of refraction of this material?
    Note: what formula should I use?
  2. jcsd
  3. Mar 29, 2004 #2
    Use Snell's Law
  4. Mar 30, 2004 #3
    angle problems

    Problem 13.
    A ray of light traveling in air strikes the midpoint of one face of an equiangular glass prism (n=1.65) at angle of exactly 30.0 degrees.
    Trace the path of the light ray through the glass and find the angle of incidence of the ray at the bottom of the prism. Answer in degrees.
    Note: The triangle is 60-60-60 degrees.

    Problem 15.
    Light strikes the surface of a prism, n=1.78. If the prism is surrounded by a fluid, what is the maximum index of refraction of the fluid that will still cause total internal reflection within the prism?
    Note: The triangle is 90-45-45 triangle.
  5. Jul 12, 2011 #4
    For problem 4:
    Given: Angle of incidence = 25.6 degrees
    n1 or medium1 = 1.00 (air)
    n2 or medium2 = 1.50 (glass)
    Required: Angle of Refraction
    Equation: n1 x sin (angle of incidence) = n2 x sin (angle of refraction)
    Derivation of the formula to get the angle of refraction:
    Angle of Refraction = { n1 x sin (angle of incidence) / n2 } sin -1
    Note: when we transpose the sin from one side to one another it becomes sin-1
    Solution: (Substitution)
    Angle of Refraction = { 1.00 x sin (25.6) / 1.50 } sin-1

    Angle of Refraction = 16.74 degrees or 16 degrees, 44 minutes and 30.04 seconds in DMS

    Why don't you try doing problem 6 for on your own this time? You will only need to do the same. Good luck..take note of the formula.. :) HInt: the new formula you're going to use is

    n2 = n1 x sin (angle of incidence) / sin (angle of refraction) :)
    Last edited: Jul 12, 2011
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