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Charge on a Spherical Shell

  1. Oct 22, 2009 #1
    If a spherical shell has a net charge of say +4.0micro coulombs do I assume that this charge is equally distributed between the inner and outer surfaces of the shell (ie +2.0 micro coulombs on the inner surface and +2.0 micro coulombs on the outer surface)?

    Thanks

    *This is not homework. I'm trying to test my understanding.
     
  2. jcsd
  3. Oct 22, 2009 #2
    No- I can tell you this instantly by thinking about what would happen if you change the inner and outer radii of the shell- which you have unspecified- to extremes. If the inner radius is 0.1m and the outer one is 100m, does it make sense that half the charge is on the 4*pi area inner surface, and half is distributed on the 10,000*pi area outer surface? That certainly doesn't minimise repulsion!

    I think the charge is stored on the outer edge- but I am not certain, some line of reasoning is telling me it is uniform but this doesn't seem very intuitive to me either.
     
  4. Oct 22, 2009 #3

    Doc Al

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    Staff: Mentor

    No. How the charge distributes itself depends upon whether there is charge contained within the shell. Consider Gauss's law with the gaussian surface through the material of the shell.

    If there are no other charges, then all the charge will be on the outer surface.
     
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