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Homework Help: Metal sphere left by alien civilization

  1. Feb 1, 2009 #1
    voltage/charge problem

    1. The problem statement, all variables and given/known data
    Imagine a small metal sphere left by some alien civilization is floating in space. A
    probe is launched directly at the sphere in order to study it. When the probe is
    1000 m from the sphere, it detects a voltage of 110.0 V; and when it’s at 100.0 m
    it records 10.0 V. What, if any, is the charge on the sphere?

    2. Relevant equations

    I used V = (kq)/r

    3. The attempt at a solution

    Solve for q to get q = V(r/k). Plug in the values for each situation, and get q. The thing is, I get different values of q for each set of values. I must be using the wrong equation...but I can't figure which equation to use that relates charge and volts.

    Last edited: Feb 1, 2009
  2. jcsd
  3. Feb 1, 2009 #2
    help anyone?
  4. Feb 3, 2009 #3

    It's due tomorrow!
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