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Why dont metal objects such as a nail get charged by friction like the famous comb,

  1. Mar 14, 2008 #1
    Why dont metal objects such as a nail get charged by friction like the famous comb, plastic rod or glass rod - all insulators?
     
  2. jcsd
  3. Mar 14, 2008 #2
    electric discharge through gases

    Can some one kindly explain or give a reference link that explains why it happens what it happens in electric discharges through gases like William Crookes expermient of 1870s and JJ Thomsons experiments with cathode rays? Covering also such important aspects such as what would have happened if we did not remove air/gas in the tube? Why electrons did not ionise the gas inside at low pressures etc? Thanks in advance. Basically, I want to know how our present knowledge of atomic structure explains the experiments and its results?
     
  4. Mar 15, 2008 #3

    russ_watters

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    Staff: Mentor

    They do.

    You can make a compass this way. Googling, I can't seem to find it, but I was a Boy Scout.... (I'm curious, so I'll look more tomorrow)
     
  5. Mar 15, 2008 #4

    pam

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    On an insulator, like a comb, the transferred charged stays where it was placed.
    In a metal, the charge spreads over the entire surface of the metal, so that the surface charge density is usually small.
    There are cases where the charge transferred to a metal can build up.
    This happens in the van der Graaf generator.
     
  6. Mar 15, 2008 #5

    pam

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    No charge is transferred when a boy (or girl) scout magnetizes metal.
     
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