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Homework Help: Gauss's Law problem

  1. Jan 12, 2008 #1
    1. The problem statement, all variables and given/known data

    Ok so I', having some problems with Gauss's law. I know what it is, but I still cant get the answers right.

    A metallic sphere of diameter 2*10-2m has been given a charge of 2 nC. State Gauss's law. Use this to determine the electrical field at the surface of the sphere. What is the electrical field inside the field?


    2. Relevant equations

    integral (E.dA)=Qenclosed/permitivity of free space


    3. The attempt at a solution

    the fist part is the equation written below.

    However im not sure about the next part. How do I distinguish between the charge inside the spehere and the charge on the surface?

    Thanks
     
  2. jcsd
  3. Jan 12, 2008 #2

    Doc Al

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    Staff: Mentor

    Assuming electrostatic equilibrium, what's the charge inside a conductor?
     
  4. Jan 12, 2008 #3

    Not really sure. Is it zero? Becasue all of the charge passes through it?
     
  5. Jan 12, 2008 #4

    Doc Al

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    Staff: Mentor

    Key fact (where electrostatic equilibrium holds): The electric field is zero everwhere inside a conductor. All the (net) charge on a conductor lies on its surface.
     
  6. Jan 12, 2008 #5
    thanks
     
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