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Homework Help: Thin film intereference basic question

  1. Feb 28, 2010 #1
    This is not a homework problem but a general problem I've been having when studying for physics.

    What is the formula for "thickness" for thin film interference problems?

    I read somewhere that there are a variety of equations that can be used--depending on interferences, and etc--however, I just need a solid list of formulas.

    I've looked through my book and the Internet, and I'm finding a variety of formulas, but none of these sources tell me when to apply each specific thickness formula.

    Can anyone provide a list of formulas and when to use them?

    I would greatly appreciate any assistance!
  2. jcsd
  3. Feb 28, 2010 #2


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    Sorry, there is no such formula. The reason is that the same formula that gives the thickness for constructive interference for one film will give the thickness for destructive interference for another film. It all depends on the relative indices of refraction between the thin film and the two media on either side of it. You need to consider each case on its merits.
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