1. Not finding help here? Sign up for a free 30min 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!

Charge of Shell

  1. Feb 12, 2008 #1
    A shell with a charge of -5.0E-6 C at the center. What will the charge be on the inner surface of the shell? The outer?
     
  2. jcsd
  3. Feb 12, 2008 #2

    Shooting Star

    User Avatar
    Homework Helper

    Is the shell made of a conducting material?
     
  4. Feb 12, 2008 #3
    It doesn't say. The first part of the question says, "A thin spherical shell of radius 15.0cm with total charge of 33.0E-6 C distributed uniformly on its surface."
    If there was a ball of charge of -5.0E-6....
     
  5. Feb 12, 2008 #4

    Shooting Star

    User Avatar
    Homework Helper

    I presume it's a conductor, since the charge on the inner surface changes with the introduction of charge in the centre. So, what do you know about induced charges on the inside surface of a conductor?
     
  6. Feb 13, 2008 #5
    I would think that the charge on the inner shell would be +5E-6, so would that make the outer 0 to keep an overall neutral charge on the shell?
     
  7. Feb 13, 2008 #6

    Shooting Star

    User Avatar
    Homework Helper

    If there's an induced charge of +q on the inside, where's the -q gone, to keep the shell have overall zero charge? How can a charge of 0 on the outer surface keep it neutral, as you've written?
     
  8. Feb 13, 2008 #7
    Because the charge in the center is (-), that would make the charge closest to it (inner) opposite in sign (+5E-6) leaving the outer surface zero.
     
  9. Feb 13, 2008 #8

    Shooting Star

    User Avatar
    Homework Helper

    The conductor was initially neutral. You've put -q at the centre, and saying that now there's +q on the inner surface and 0 on the outer surface, which makes the system overall neutral. How can that be, when you've introduced some -q in the system?

    If +q is induced on the inner surface, there must be a -q somewhere to balance it.
     
    Last edited: Feb 13, 2008
  10. Feb 13, 2008 #9
    So would the outer surface also be +5E-6?
     
  11. Feb 13, 2008 #10

    Shooting Star

    User Avatar
    Homework Helper

    -5E-6; -q at the centre, +q on the inner surface, and -q on the outer surface.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?