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Homework Help: Interface dielectrics

  1. Mar 3, 2008 #1
    1. The problem statement, all variables and given/known data
    A coaxial cable has a line charge running through it's center with a line charge density [tex]\lambda[/tex]. There is a dielectric filled between the line charge and the first conducting shell cylinder and another dielectric between the outer cylindrical shell and the inner cylindrical shell.



    2. Relevant equations
    [tex]D_{1n} - D_{2n} = \rho_s[/tex]


    3. The attempt at a solution

    My question is, in the equation to the bottom will rho have a value? Since the line charge is the only thing with direct charge on it, can I ignore the fact that there is a conductor separating the dielectrics?
    I know the inner conductor will have a negative charge to counteract the field coming from the line charge, but with that equation isn't it applicable if the surface is directly charged?

    so can i just say [tex] D_{1n} = D_{2n} [/tex] in this case anyway?
     
  2. jcsd
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