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Homework Help: Electric Potential find the potential at its center

  1. Sep 25, 2008 #1
    1. The problem statement, all variables and given/known data

    A thin plastic rod 15 cm long carries 4.2 nC distributed uniformly over its length.
    (a) If the rod is bent into a ring, find the potential at its center.
    (b) If the rod is bent into a semicircle, find the potential at the center (i.e., at the center of the circle of which the semicircle is part).

    2. Relevant equations

    V = KQ/r potential at a point.

    3. The attempt at a solution
    when bending the rod, how to find the distance r.
     
  2. jcsd
  3. Sep 25, 2008 #2

    cepheid

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    If a 15 cm rod is bent into a circle, then it will be a circle 15 cm in circumference. What is the radius of a 15 cm circumference circle?
     
  4. Sep 25, 2008 #3
    Circumference=2(pi)r
     
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