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Self inductance question

  1. Aug 28, 2009 #1

    the formula for magnetic field
    is like they show but its not divided by l
    like they did

    i cant see a reason why they present it that way
  2. jcsd
  3. Aug 28, 2009 #2


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    You mean in the equation for [itex]M[/itex]?

    If so, [itex]M[/itex] is the mutual inductance and by definition,

    [tex]\Phi_{\text{total}}=MI\implies M=\frac{\Phi_{\text{total}}}{I}[/tex]
  4. Aug 28, 2009 #3
    i am asking about the previous step
    when they found the magnetic field
    and the expression has l in the denominator

  5. Aug 28, 2009 #4


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    Sorry, the lower case 'L' in your post looked a lot like an upper case 'i' the first time i read it....

    [tex]\frac{N_b}{l}[/tex] would give you th number of turns per unit length in the solenoid, which is what [itex]n[/itex] represents in the version you are probably used to seeing: [itex]B=\mu_0 n I[/itex].
  6. Aug 28, 2009 #5
    thanks :)
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