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Does a constant magnetic field cause a current?

  1. Feb 16, 2015 #1
    (1) I previously learned that a constant magnetic field causes a force on any electrons within its range. Clearly, this force would cause electrons to move. Isn't this creating a current?

    (2) However, now apparently I am told that the only varying magnetic fields can create a current. I.e., turning a magnetic field on and off.

    I am confused about this. Doesn't the first statement imply that a constant magnetic field can create a current?
  2. jcsd
  3. Feb 16, 2015 #2


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    hi x86

    The force on a charge (electron) from a magnetic field is proportional to q x v (law of Biot-Savart). If v = 0, ( ie. the magnetic field and the electron are stationary) there is no force.

    That's correct, so ....
    1) turn magnetic field on and off
    2) just moving the magnet ( field)
    3) or by moving the conductor in a magnetic field.

    There has to be relative motion between the field and the conductor

    Last edited: Feb 16, 2015
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