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Homework Help: A dielectric in side a spherical shell

  1. Dec 4, 2008 #1
    Assume that there is a spherical dielectric inside spherical shell. There is a vacuum between the dielectric and the shell.

    I found this configuration rather tricky. Any idea ?


    http://img117.imageshack.us/img117/7413/conductorwf9.jpg [Broken]
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Dec 4, 2008 #2
    I'm not clear on your specific question. Could you elaborate?
  4. Dec 4, 2008 #3
    Consider the diagram above. Assume that the didelectric in the middle of shell contains charge Q. With this fact, how should the electric field be determined ?
  5. Dec 4, 2008 #4


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    Homework Helper

    Why is this tricky? What can you say about the E-field from Gauss law?
  6. Dec 5, 2008 #5
    FourierX, there are a few "rules" that, if you are aware of them, will enable you to solve your problem:

    • The electric field outside of a uniformly charged sphere is the same as if all the charge were concentrated at its centre-point. This is true whether the sphere is hollow, solid, conductive or dielectric. This is also true of a hollow conductive shell which contains within its cavity any static arrangement of charges.
    • The electric field inside a hollow conductive shell is zero.
    • The electric field inside the body of a conductor is zero.

    I would suggest that you have a try at deriving the above rules yourself. The maths is not difficult and your understanding will increase in the process. Best of luck.
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