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Homework Help: Fermi Numbers?

  1. Sep 28, 2004 #1
    Fermi Numbers!??

    I'm trying to solve this problem and explain all my steps in my reasoning.


    If anyone can help me figure this out, reply
    thanking u in advance
  2. jcsd
  3. Sep 28, 2004 #2
    No Replies :( :'(
  4. Sep 28, 2004 #3
    :"( ...............................
  5. Sep 28, 2004 #4

    Claude Bile

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    No of hairs on head is equal to;

    No of hairs per unit area x Surface area of head with hair.

    You need to get a value for both of these quantities, either through measurement or estimation (or both).

  6. Oct 1, 2004 #5
    this is hard lol
  7. Oct 1, 2004 #6


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    Gold Member

    Using the average diameter of a hair (about 50 microns, or pluck a few hairs and measure them) you can determine a rough upper limit on the number of hairs. The actual number depends on the packing density, which I think, is not likely less than 10% coverage. So that gives you an approximate lower bound. Pick the mean to get an order of magnitude estimate.
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