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: Charged insulator

  1. Jul 8, 2007 #1
    1. The problem statement, all variables and given/known data
    a circular ring made of an insulating material is cut in half. one half is given a charge -q uniformly distributed along its arc. The other half is given a charge +q also uniformly distributed along its arc. The two halves are then rejoined with insulation at the junctions J as shown. If there is no change in the charge distributions, what is the direction of the net electrostatic force on an electron located at the center of the circle?

    [i've attached the picture of the circle for a better visual. ]

    2. Relevant equations

    3. The attempt at a solution

    I think the direction would be downwards but I'm not entirely sure. My reasoning is that because the top half of the circle is negatively charged while the bottom half is positively charged, the electron (negatively charged) would be attracted to the positive charges while repelled by the negative charges thus the force would put down. Is this correct?

    Attached Files:

  2. jcsd
  3. Jul 9, 2007 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Yes, that's correct. The field points upwards; the force points downwards.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook