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Beyond Lorentz force

  1. Apr 18, 2014 #1
    When a wire is placed in a magnetic field, Lorentz force acts on an electron in a direction perpendicular to velocity and to the magnetic field, since the magnetic force is perpendicular to the velocity the electron will only change direction with no velocity change, what happens after that, I have heard that the electron will move in circles, is that true??
  2. jcsd
  3. Apr 18, 2014 #2


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    A free electron moves in circles (assuming the field spreads out wide enough to cover that), but electrons in a wire cannot just leave that, so they follow the wire.
  4. Apr 21, 2014 #3
    We can say that if the force was not perpendicular to the velocity will have an ever-increasing force and velocity
    Violating the law of conservation of energy
  5. Apr 22, 2014 #4

    Philip Wood

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    Just a very small point, but one which could cause you confusion… If the electron changes direction it's velocity is bound to change. That's because the velocity vector gives the direction of travel as well as the speed. [Velocity may be defined as the displacement (a vector) per unit time.] What you meant was that "the electron will only change direction with no speed change".
  6. Apr 22, 2014 #5

    I meant the magnitude of the velocity
  7. Apr 23, 2014 #6

    Philip Wood

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    I thought you probably did mean this, but using technical terms correctly is a good habit to get into.
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