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What causes potential difference in the conductor?

  1. Mar 15, 2014 #1
    What cause potential difference in the conductor? I mean why the changing magnetic flux induce EMF? I understand the basics but I can't understand it. What I know: there is free electrons on the surface of a copper conductor. Electron have electric field vector and magnetic field vector and these are perpendicular. Electric vector point to the protons/core usually but these are delocalized electrons. In a changing magnetic flux these electrons always turn to the opposite side of flux with their magnetic vector but don't move. That's all, just turn. Why build it EMF? Where is the potential difference?
     
  2. jcsd
  3. Mar 15, 2014 #2

    tiny-tim

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    Hello George! Welcome to PF! :smile:
    No, you are treating "a changing magnetic flux" as if that is all there is.

    You cannot have a changing magnetic field without an electric field

    Faraday's Law (one of Maxwell's equations) says ∂B/∂t = -curlE

    it's that E which cause the electric potential difference! :wink:
     
  4. Mar 15, 2014 #3

    OK, I know the equation and all what you say. But what is the quantum physics explanation of this EMF? You mean if the magnetic field sort electrons in the same direction the electric field vectors of these also will point in one direction and this cause EMF? But why these electrons start to move in a short circuit?
     
  5. Mar 15, 2014 #4

    tiny-tim

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    Sorry, George, but I don't know what you mean. :confused:

    A changing magnetic flux includes an electric field.

    That electric field (obviously) affects the electrons, and it induces a current in a conductor.
     
  6. Mar 15, 2014 #5

    bhobba

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