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Homework Help: Find index of refraction

  1. Feb 13, 2013 #1
    1. The problem statement, all variables and given/known data

    A beam of light travels through air (n= 1.0003) and strikes an unknown material at an angle of 50.0 degrees. The new angle of refraction is 25.0 degrees. What is the index of refraction of this material?

    2. Relevant equations

    sin[itex]\theta[/itex]2 / sin[itex]\theta[/itex]1 = n1/n2

    3. The attempt at a solution

    sin(25)/sin(50) = 1.0003/n2

    .504 = 1.0003/n2

    .504= n2

    ---It is multiple choice test and my answer isnt any of the options. The options are

    A) .709
    B) .643
    C) 1.20
    D) 1.81
  2. jcsd
  3. Feb 13, 2013 #2
    Re: High School Physics Help. Urgent!!!

    Try writing sin(θ1)/sin(θ2) = n1/n2 as an equation where n2 = n1 / ... . Then plug in your variables all at once and compute (you may be loosing accuracy by not capturing enough digits).

    Edit: Also, remember radians = degrees * 180 / [itex]\pi[/itex].

  4. Feb 14, 2013 #3
    Re: High School Physics Help. Urgent!!!

    The equation you're using is the correct one.

    Your value for sin(25)/sin(50) is not correct, ( you're using radians instead of degrees )
    Also, going from the 2nd to the 3rd line of your solution is wrong.

    Note that the refracted angle is less than the incident angle - what does that tell you about n2?
  5. Feb 14, 2013 #4
    Your calculator was set for radians, not degrees.
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