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Homework Help: Capacitor homework problem

  1. Feb 18, 2005 #1
    A capacitor C1 carries a charge Q0. Is is then connected directly to a second, uncharged, capacitor C2.

    What charge will each carry now? Q1 = Q0C1/(C1 + C2); Q2 = Q0C2/(C1 + C2)


    What will be the potential difference across each?
    V = Q0 / (C1 + C2)

    -------||-------||--------
    |*****C1*****C2******|
    |********************|
    |********************|
    |********************|
    |_______________________|

    I know that the formula Q = CV is used, but how do you manipulate it (other than V = Q/C) to get the answers in bold?

    Thanks.
     
  2. jcsd
  3. Feb 18, 2005 #2

    StatusX

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    Homework Helper

    The voltage around the loop will be 0 in equilibrium, and whatever charge the second capacitor gets, the first one must lose. Does that help at all?
     
  4. Feb 18, 2005 #3

    Doc Al

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    Staff: Mentor

    Since the capacitors are connected in parallel, they have the same voltage (V). So the charges on the capacitors are: [itex]Q_1 = C_1V[/itex] and [itex]Q_2 = C_2V[/itex]. The total charge remains the same, so [itex]Q_0 = Q_1 + Q_2[/itex]. Solve for V.
     
  5. Feb 18, 2005 #4
    I think I understand what you're saying, but I don't know how to apply it to the questions.
     
  6. Feb 18, 2005 #5
    Oh, OK. Let me try it.
     
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