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I Faraday cage in electrodynamics (with currents)

  1. Sep 22, 2016 #1

    Assume a long hollow wire that both carries a nonzero net charge and a current. Is it still true that all charge sits on the outer surface of the cable and that the empty space inside is field-free (Faraday cage)? I know proofs of those facts in electrostatics using Gauss' theorem, but they rely on the fact that there's no electric field inside a conductor, which is not the case in general electrodynamics, for example when there's a current.
  2. jcsd
  3. Sep 22, 2016 #2


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    Right. There's a small driving electric field inside a current carrying conductor because of surface charges.
    This is true only in electrostatic equilibrium.
  4. Sep 23, 2016 #3
    I think that that electric field won't be zero inside the wire ie the hollow part
  5. Sep 24, 2016 #4
    Most examples and experiments of Faraday cages I know appear in dynamic conditions (i.e. with currents): The inside of a car or airplane struck by lightning is save, a radio or cellphone loses reception when wrapped with aluminium foil and so on. Why do they still work under non-electrostatic conditions?
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