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Insulator and electron problem

  1. Sep 8, 2008 #1
    1. If an object is determined to have a negative charge of 160 NC, you can conclude that the object has an excess of
    a. 10^ 9 electrons
    b. 10^10 electrons
    c. 10^11 electrons
    d. 10^12 electrons
    e. 10^13 electrons

    I came up with c. 10^11 electrons by taking 160E-9C/1.6E-19C = 10^11. I just used numbers that I found so I'm not sure if this is right and if it is I don't understand the reasoning as to why it is correct. Any help would be appreciated

    I also have one more question.

    If you bring a negatively charged insulator near two uncharged matallic spheres that are in contact and then separate the spheres, the sphere on the right will have
    a. no net charge
    b. a positive charge
    c. a negative charge
    d. either a positive or negative charge
    e. none of the above
  2. jcsd
  3. Sep 8, 2008 #2


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    Homework Helper

    Re: Electrons

    A small careless mistake here. You should have 10x10^11 which is 10^12.

    Is there a picture of this? The question asks for "the sphere on the right", and I'm assuming that the setup isn't symmetrical to begin with.
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