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: Charge on spheres connected by wire

  1. Feb 19, 2009 #1
    1. The problem statement, all variables and given/known data

    A total charge of 2.600 C is shared by two metallic spheres A (radius 7.00 cm) and B (radius 5.00 cm) that are connected by a thin wire of length 1.00 m. Find the charge on sphere A. (Note that the influence of sphere B is not negligible.)

    2. Relevant equations

    I presume that (kq)/r will come into play, and also that Q1+Q2 will equal 2.600 C

    3. The attempt at a solution

    I know that for a similar problem where the distance between the two spheres can be considered large enough that their influence is negligable that the problem can simply be solved by rearranging q1+q2=2.6C to find one of the charges in terms of the other, and substituting that result into (kq1)/r1=(kq2)/r2 will allow one to find the charges.

    However, I don't know how to approach the problem in the knowledge that the influence of one sphere on the other is no longer negligable. I suspect it will have an influence on how I equate the potentials, but I'm not sure exactly how. Any suggestions?
     
  2. jcsd
  3. Feb 19, 2009 #2
    Figured it out. :)

    I'm sure I'll have another electric field/electric potential question coming up for you guys over the next few days though, so you'll have another oppurtunity to welcome me :P
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook