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Homework Help: Intensity Question

  1. Dec 1, 2013 #1

    Can someone please explain why the are used is 4∏D2? Shouldn't it just be ∏r2?
  2. jcsd
  3. Dec 1, 2013 #2
    The intensity spreads out over the surface of a sphere. Your formula is for the area of a circle.
  4. Dec 1, 2013 #3
    That makes much more sense! Can't believe I totally missed that. Thank you!
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