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Homework Help: General questions about conductors in electrostatics

  1. Sep 1, 2011 #1
    These are just some general questions I have about what I'm reading in my physics book. I'm really having trouble visualizing what happens to electrons in conductors (this is all for electrostatics btw).

    Three scenarios:

    (1) A solid conductor
    Why is the charge only on the surface of the conductor in electrostatics? (I understand that electrostatics means that the electrons cant have a net-motion so the E-field has to be zero, but how do all the charges come to pile up on the outside of the conductor? Wouldn't all the like-charges repel each other? My book shows a diagram with a bunch of positive charges along the outside of the conductor.)

    (2) A conductor with an empty cavity


    (3) A conductor with a cavity and a charge in the center of the cavity
    For instance, a positive charge q in the center will result in a charge q+q_c on the surface of the conductor (where q_c is the original charge of the conductor without the cavity or charge in the center). Why? The diagram also shows that the surface of the cavity has a charge -q, but where does the -q come from physically if all we've added to the system is the +q charge?
     
  2. jcsd
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