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Homework Help: Magnetomotive force and the H-field

  1. Aug 28, 2012 #1
    1. The problem statement, all variables and given/known data

    The magnetomotive force is given as an integral of the H-field. I want to know how this can be a force.

    2. Relevant equations

    [tex]\int H \cdot d \ell = F[/tex]

    3. The attempt at a solution

    So a bit confused. Wiki says that this equation

    [tex]\int H \cdot d \ell = F[/tex]

    is a force, the magneto-motive-force. But this is the H-field multiplied by a length [tex]\ell[/tex]. From what I knew about the H-field, if you multiply the H-field with a length, you should get a current, not a force as

    [tex]\int H \cdot d\ell = I[/tex]

    I know this because

    [tex]H = \frac{I}{2\pi r}[/tex]

    you can see why by rearranging it

    [tex]H \cdot r = \frac{I}{2\pi}[/tex]

    so what gives?

    Thanks in advance.
  2. jcsd
  3. Aug 28, 2012 #2


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    Staff Emeritus
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    It's analogous to electromotive force. Neither electromotive force or magnetomotive force is a force in the traditional sense. That is, it's not measured in newtons in the SI unit system.
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