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Homework Help: Rod A is a positively charged insulator.

  1. Oct 3, 2007 #1
    Rod A is a positively charged insulator. Bob C and a second rod B are in contact with each other and made from conducting material. Rod B is fixed, and C is suspended from a wire and free to swing. Briefly describe what happens when A is brought near B. (I would draw a diagram but i cant figure out how to get it to go with my post).

    since A is positively charged I thought that when you brought it near to the fixed rod B that rod B would become polarized. This resulting polarization would then polarize the bob(ball) hanging from the string that is in contact with it. Apparently I am missing something because this is slightly incorrect
  2. jcsd
  3. Oct 3, 2007 #2


    Staff: Mentor

    C and B are conductors and are in contact with one another, so charges may move freely between the two. As A is brought near B its net positive charge will attract negative charges toward it. As negative charge accumulates in B, by conservation of charge, an equal amount of positive charge must accumulate in C.
  4. Oct 3, 2007 #3
    so then Rod B would become negatively charged and the ball would become positively charged?
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