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Electric potential question.

  1. Apr 26, 2009 #1
    1. The problem statement, all variables and given/known data

    Two spherical conductors of radii r1 and r2 are separated by a distance much greater than the radius of either sphere. The spheres are connected by a conducting wire as shown in the figure. The charges on the spheres in equilibrium are q1 and q2, respectively, and they are uniformly charged

    25-25.gif

    What if initially a charge 2.5 C is put on shell #1 with radius 4.3 m, then a far away shell #2 (initially neutral) with radius 7.3 m is connected to shell #1 by a long conducting wire.
    (a) What is the final charge on shell #1?


    (b) What is the final charge on shell #2?


    (c) What is the electric potential V on shell #1?



    (d) What is the electric potential V on shell #2?



    2. Relevant equations

    V=ke(q/r)


    3. The attempt at a solution

    I know that the electric potentials of the two shells are equal due to the conducting wire. It says that the conducting wire is "long" so I believe they behave like point charges and I would use the equation I listed. So I figured I would set the equations for the two shells equal and solve, like so:

    ke(q1/r1) =
    ke(q2/r2)

    and solve for the unknown q. I thought this would give me the answer to part A but I was marked wrong... can anyone tell me what I'm doing incorrectly?

    Thanks
     
    Last edited: Apr 26, 2009
  2. jcsd
  3. Apr 27, 2009 #2
    Nevermind, I got it.
     
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