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Confusion about the nature of Diffraction.

  1. Dec 31, 2013 #1
    Why does the size of an obstacle have to be comparable to the wavelength of radiation for diffraction effects to be noticable ? Secondly, if the size of an opening is much smaller than the wavelength of the radiation , how does the radiation interact with the opening ? Third, can the same things be concluded for phonons traveling in a crystal lattice, or mechanical waves on a string ?
  2. jcsd
  3. Dec 31, 2013 #2


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    The amount of light that goes straight through a wide aperture is large compared to the amount that is diffracted by the edges of the aperture.
  4. Dec 31, 2013 #3


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    Do a Google search for "Fresnel diffraction" and you'll find examples of diffraction at the edges of a wide aperture. Also try "knife edge diffraction" for diffraction at a single edge (semi-infinite aperture).
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