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Total internal reflection

  1. Nov 27, 2003 #1


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    The drawing shows an optical fiber that consists of a core made of flint glass (nflint = 1.667) surrounded by a cladding made of crown glass (ncrown = 1.523). A beam of light enters the fiber from air at an angle q 1 with respect to the normal. What is q 1 if the light strikes the core-cladding interface at the critical angle q c?http://edugen.wiley.com/edugen/courses/crs1000/art/images/c26/nw1183-n.gif

    i know u have to use snell's law

    sin theta = (n2/n1), but i don't know what to do from here.

    The text book in which this problem is in gives no info on these kinds problems. Please help me
  2. jcsd
  3. Nov 27, 2003 #2

    Tom Mattson

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    You have to use Snell's law twice. You have to do it once to find the critical angle (considering the cladding-core interface) and then you have to do it again to find θ1 (considering the core-air interface).
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