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Homework Help: Electric field magnitude

  1. Feb 17, 2005 #1

    If you have a solid metal sphere of radius r0 (let's say r0 = 1 m), and you are calculating the magnitude of the electric field at r = .9 m. Why is the electric field equal to zero when r is less than r0? Is it because the sphere is solid? (I don't think this is true for a hollow sphere?)

  2. jcsd
  3. Feb 17, 2005 #2

    Doc Al

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    Staff: Mentor

    Right. Once electrostatic equilibrium is reached (that is, when the charges stop moving), the electric field anywhere within a conductor is zero. By "within" I mean within the actual conducting material, not inside a hollow space. For example, if a charge were place at the center of a hollow conducting sphere, the field would be non-zero inside the hollow, but zero in the metal itself.
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