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Quick Conductor Question

  1. Apr 21, 2007 #1
    Why is it that BOTH electric AND magnetic fields are zero inside the conductor. My book says that the H-field is zero due to the fact that the E-field is zero but doesn't give any detailed explanation.
  2. jcsd
  3. Apr 21, 2007 #2


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    I think you already saw the post regarding zero E field. In an ideal conductor any H field will induce eddy currents at the surface that perfectly cancel the magnetic field inside.
  4. Apr 21, 2007 #3


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    also, if you think about it using Maxwell's equations, if for a non-zero volume the E field is identically zero at all locations and in time, then there is no dE/dt as a source of a magnetic field. and because

    [tex] \nabla \cdot \mathbf{B} = 0 [/tex]

    there are no sole (monopole) sources of a magnetic field.
  5. Apr 22, 2007 #4
    Great! Thanks guys. :smile:
  6. Apr 22, 2007 #5


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    Actually this is not entirely correct. According to *classical* EM, a perfect conductor cannot have any *change* in magnetic field, but it can have in principle a non-zero static magnetic field. It is a pure quantum effect that a superconductor cannot have a magnetic field inside. If it were a classical perfect conductor, it would simply "freeze in" the existing magnetic field at the moment of its transition to "perfect conductor".
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