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Homework Help: Total Internal reflection question

  1. Dec 9, 2007 #1
    1. A white light source is below the lower surface of a piece of optical-quality glass. The glass has an index of refraction of 1.520 for red light and 1.538 for violet. If you were able to move your eye at any angle relative to the perpendicular to the glass, calculate A) Which color disappears first due to total internal reflection B) At what angle do you see only a single color, red or violet?

    2. critical angle = sin-1(n1/n2)

    3. So far I have done the following
    critical angle = sin-1(1.00/1.520) =41.1degrees for red
    critical angle = sin-1(1.00/1.538) =40.6degrees for violet
    The index of refraction for glass is 1.523
    critical angle = sin-1(1.00/1.523) = 41.0 degrees
    Therefore the red light would disapear first because its critical angle is bigger then that of 41.0 degrees.
    part B) the angle would be anything greater then 41.0degrees the only the violet light would be visible.
    Is this correct?
  2. jcsd
  3. Dec 9, 2007 #2


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    The index of refraction for glass is 1.523 For which color?
  4. Dec 10, 2007 #3
    The index of refraction for glass is 1.523, for white light.
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