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Homework Help: Induced magnetic fields

  1. Dec 3, 2008 #1
    A parallel-plate capacitor, C=5 mircoF, has closely spaced circular plates of radius R = .1m.

    How much displacement current is encircled in a loop of r=.05m that is centered on the axis between the plates when a uniform electric field between these plates changes with time at the rate of 9*10^12 V/ms during the charging process? What is the magnitude of the induced magnetic field at r=.05m?

    Dissipative current = [tex]\epsilon[/tex]_0 * d[tex]\phi[/tex]_e/dt
    or [tex]\epsilon[/tex]_0 * A *dE/dt

    And for the magnetic field B =([tex]\epsilon[/tex]_0 * [tex]\mu[/tex]_0 * A *dE/dt)/ 2*pi*r

    Now is A equal to pi*r^2 where r is equal to .05m since this is the area that the flux is going through or does A equal the ratio of the areas, r^2/R^2, since there is flux through the whole .1m radius?

  2. jcsd
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