1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Gauss Law Problem With A Spherical Conductive Shell

  1. Oct 2, 2011 #1
    You are a hollow metallic sphere of inner radius r1, and outer radius r2. Inside is a charge of magnitude Q and a distance d<r1 from the centre.

    First I need to draw the electric field lines for regions r<r1, r1<r<r2, and r2<r

    Since the sphere is a conductor the only place where there is not an electric field is inside the shell. The point charge induces a charge on the conducting sphere, making it in turn create an electric field outside the sphere.

    I then need to use Gauss's law to find the electric field where possible. I think this is correct:

    [tex]\int \vec{E}\cdot d\vec{A}=\frac{Q_{enclosed}}{\epsilon_{0}}[/tex]
    [tex]E\int d\vec{A}=\frac{Q}{\epsilon_{0}}[/tex]
    [tex]E(4\pi r^{2})=\frac{Q}{\epsilon_{0}}[/tex]
    [tex]E=\frac{Q}{4\pi r^{2}\epsilon_{0}}[/tex]

    For all locations that are not inside the shell. Am I correct?
    Last edited: Oct 2, 2011
  2. jcsd
  3. Oct 2, 2011 #2


    User Avatar
    Homework Helper
    Gold Member

    Looks fine to me.
  4. Oct 2, 2011 #3
    Thanks for the confirmation.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook