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Is it possible to get rid of the B field entirely?

  1. May 5, 2012 #1

    I was wondering if it is possible to use only relativity and the E field to describe the force that a moving charge feels next to a wire with a steady current in it. Is the concept of the B field necessary? It seems like if we transform into the frame of the moving point charge, we will see length contraction, which leads to the positive charges in the wire appearing to be denser than the negative charges flowing through the wire, but what about in the laboratory frame? In the laboratory frame, the wire appears to be neutral, whether there is current flowing in it or not, so is it possible for the laboratory frame to explain the force on the moving charge without having to use the B field?

    Thanks in advance for any help anybody can provide!!!
  2. jcsd
  3. May 5, 2012 #2


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    No, you will find that if E>B (in gaussian units) then this can be done, while if B>E, one cannot transform to any Lorentz frame in which there is no B field.
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