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Homework Help: Please help! How to find the potential difference of a spherical shell

  1. Sep 21, 2004 #1
    I can frankly say i'm totally confused on how to solve this problem. Here it is:

    A think spherical shell of charge Q and uniform volume charge density p is bounded by radii r1 and r1 where r2>r1. WIth V=0 at infinity find the electric potential V as a function of the distance from the centre of the distribution considering the regions:

    a) r > r2 Ans. V = kQ/r because the spherical distribution will act like a point charge when any point is taken outside the shell, by Gauss Law

    b) r2 > r > r1 Ans. completely confused here...Using the concept in the first part a) i would think from the iner radii point of view

    Vsmall = kQ/r

    but since it is enclosed in a bigger radii i have no idea how to proceed

    c) r < r1 if the previous confused me then this one is so above my head it's orbiting the earth

    d) do these results agree at r = r2 and r = r1 ... Well if i could answer b and c then i might be able to answer this one
  2. jcsd
  3. Sep 21, 2004 #2

    Claude Bile

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    Science Advisor

    c) should be easy, if the Electric field is zero inside the shell, what does this say about the potential?

    b) is a little trickier. How does the Electric field behave inside the shell? Does it go up as r^2? Use Gauss' Law if you must.

    d) The answers should agree, if not, then a mistake has been made.

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