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A physical contradiction

  1. Sep 15, 2011 #1
    So "A shell of uniform charge attracts or repels a charged particle that is outside the shell
    as if all the shell’s charge were concentrated at the center of the shell" and also, "If a charged particle is located inside a shell of uniform charge, there is no electrostatic force on the particle from the shell." However, I found this picture in the textbook: http://imageshack.us/photo/my-images/823/gha.png/
    A negatively charged particle is located inside the electrically neutral spherical shell. However, I see these electric field lines acting on the particle, which leads me to believe that there is also an electrostatic force acting on it. This contradicts the second statement above, about a particle not experiencing any force from the shell if the particle is located in the shell. Can anyone explain this to me?
  2. jcsd
  3. Sep 15, 2011 #2


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    Those electric field lines in the figure are from the charge itself, and NOT acting on the charge.

  4. Sep 15, 2011 #3

    Doc Al

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    Staff: Mentor

    Note that the charge on the inner surface of the shell is not uniformly distributed.
  5. Sep 16, 2011 #4
    Ooh. Gotcha, thanks.
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