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Polarization and decreasing intensity of light to 10%

  1. Jul 16, 2013 #1
    1. The problem statement, all variables and given/known data

    In order to decrease the intensity of a beam of unpolarized light to 10% of its original
    intensity using two polarizers, what is the required value of θ, the angle between the
    transmission axes of the two polarizers?


    2. Relevant equations

    tanθB=n2/n1


    3. The attempt at a solution

    tanθB=n2/n1

    I'm not sure how to do this. I read the section on polarization and there are no examples in the book.
     
  2. jcsd
  3. Jul 16, 2013 #2
    You seem to have mixed up Brewster's law with the Law of Malus. Check you textbook about the Law of Malus.
     
  4. Jul 16, 2013 #3
    So my equation would change to S=So=cos2θ

    Would it be:

    1/10*I=1/2*I*cos2θ ?


    1/5=cos2θ

    θ=63.4°

    ?
     
  5. Jul 17, 2013 #4
    Looks good to me.
     
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