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Homework Help: Diffraction and interference patterns

  1. Dec 6, 2008 #1
    In Young's double slit experiment, how come the interefernece pattern produced does not take into account single slit diffraction?

  2. jcsd
  3. Dec 6, 2008 #2


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    It does. It is just that since (if) the slit separation is substantially greater than the slit widths this factor dominates. You can however do a more precise calculation which takes both effects into account.

    [edit: PS] My reasoning may not quite be right w.r.t. relative widths but the rest is correct.[ end edit]
  4. Dec 6, 2008 #3


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    I agree with jambaugh. Another way of saying it is that, for a single slit difraction patern, you assume that the width of the slit is nonnegligible, whereas, for a double slit pattern, you assume that the slits are infinitesimals, like ideal line sources with zero width.
  5. Dec 7, 2008 #4
    That makes sense, thanks!
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