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Homework Help: Can't understand why the unit of Reluctance is At/Wb

  1. May 6, 2016 #1
    1. The problem statement, all variables and given/known data
    I can't figure out why the unit of Reluctance is At/Wb and not (At/Wb)m2
    This is what I have from my text book, with the red oval area being the part that I'm totally confused about
    2. Relevant equations

    3. The attempt at a solution
    So the m/m cancels out to 1 making it
    which is = (At·m2)/Wb
    then I have no idea what happened so that m2 vanished and R became At/Wb

    Please help me clear up my confusion
    I can't sleep scratching my head T_T
    Thanks a bunch!
  2. jcsd
  3. May 6, 2016 #2


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    Homework Helper
    Gold Member

    As your book says, reluctance is analogous to resistance in electrical circuits. Similarly, flux is analogous to current and mmf (Ampere turns) is analogous to voltage.
  4. May 6, 2016 #3


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    Staff: Mentor

    Note the division operator:
    The underlined bit is in the denominator of the denominator, so to speak. Hence it can be "promoted" to the numerator of the overall expression.

  5. May 6, 2016 #4
    Thank you so much!
    I think I'll need to go back to secondary algebra for a bit of revision :(
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