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: Simple conductors question

  1. May 29, 2010 #1
    1. The problem statement, all variables and given/known data
    A spherical conductor of radius R1 is charged to 28 kV. When it is connected by a long, very thin conducting wire to a second conducting sphere far away, its potential drops to 12 kV. What is the radius of the second sphere as a multiple of R1?


    2. Relevant equations
    V=kq/r
    k=8.99e9


    3. The attempt at a solution
    Seems like it should be pretty simple. I just assigned variables q1=q2, k1=k2, v1=28kV and v2=12kV and solved for r (r=kq/V). Then compared the values of R. Webassign is giving me an incorrect answer. There was a similar problem and the book and using the books numbers i got R2=.6 R1 and the solutions manual said 2/3 R1 so I'm not sure if it's a rounding error or what. Just wanted to make sure I was doing it right since I only have 1 try left on webassign before I get locked out and lose easy points.

    Thanks for any help in advance.
     
  2. jcsd
  3. May 29, 2010 #2

    ehild

    User Avatar
    Homework Helper

    Show your work in detail.

    ehild
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook