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    I'm stuck with part c) on this question, any ideas?
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    (Original post by langlitz)
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    I'm stuck with part c) on this question, any ideas?
    Maybe write down a general expression for L in terms of r, the radius at which the medium starts, and differentiate to find a maximum.

    More physically, note that B \propto \frac{1}{r} inside the coax, so you want to put the "strengthening effect" of the medium as close to the inner cylinder as possible, as that will increase \Phi \propto L.
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    (Original post by atsruser)
    Maybe write down a general expression for L in terms of r, the radius at which the medium starts, and differentiate to find a maximum.

    More physically, note that B \propto \frac{1}{r} inside the coax, so you want to put the "strengthening effect" of the medium as close to the inner cylinder as possible, as that will increase \Phi \propto L.
    Ah thanks, I see now

    I get
    L=\frac{\mu_o}{2\pi} (\mu_r ln(\sqrt{6})+ln(4/\sqrt{6})
    as the maximum inductance
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    (Original post by langlitz)
    Ah thanks, I see now

    I get
    L=\frac{\mu_o}{2\pi} (\mu_r ln(\sqrt{6})+ln(4/\sqrt{6})
    as the maximum inductance
    I agree (via the 2nd method - haven't tried the 1st).
 
 
 
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