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Homework Help: Electrostatics question, need help

  1. Feb 4, 2009 #1
    Electrostatics question, need help urgent!!

    1. The problem statement, all variables and given/known data
    A small metal sphere carrying a charge of -2Q is first brought into contact with sphere R Which has a charge of +Q, and then into contact with sphere S which has a charge of +2Q, and finally into contact with sphere T which has a charge of +3Q. After making contact with the three spheres, in the stated order, the charge on the sphere at T is?

    2. Relevant equations


    3. The attempt at a solution

    Honestly, I've never learnt how to do these sort of questions. I'd just like some insight on how to do these types of questions! any help is muchly appreciated ! please help, thankyou
  2. jcsd
  3. Feb 4, 2009 #2


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    Homework Helper

    Re: Electrostatics question, need help urgent!!

    If the charged spheres are identical, the net charge will be shared equally by them. In the first case, after contact the net charge is -Q. So the charge on each sphere is - Q/2.
    In similar way try the other cases.
  4. Feb 4, 2009 #3
    Re: Electrostatics question, need help urgent!!

    Thank you. I understand how to do the question now. The answer is +15/8 Q.
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