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Polarizing filters

  1. Jul 9, 2008 #1
    Which combo of polarizing filters allows most light to pass through? Each orientation is given with respect to vertical
    unit of following values given are angles:
    1. 0, 45, 90
    2. 30, 60, 90
    3. 180, 0, 180
    4. 90, 135, 180
    5. 10,20,100

    I tried by using the formulas:

    so bascially I multiplied cos^2(theta1) *cos^2(theta2) *cos^2(theta3) and chose the biggest value. Am I doing this right? Can I just plug in the angles given directly or do I have to subtract something from them?
  2. jcsd
  3. Jul 9, 2008 #2


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    Science Advisor
    Homework Helper

    Hi solars! :smile:

    Isn't it the difference between the angles that matters?
  4. Jul 9, 2008 #3


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    I've done this experiment for real (when I worked in a camera store).

    It's really cool.

    Put 2 filters together at 90 degrees to each other. Completely opaque.
    Slip a 3rd one between them at a 45 degree angle. Suddenly, you can see through all three!

    Manager says "How does that help us sell more accessories?"
  5. Jul 9, 2008 #4
    oh so it should be 3 then? thanks for the help guys =)
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