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Homework Help: Capacitor circuit

  1. Apr 14, 2008 #1
    1. The problem statement, all variables and given/known data

    In the circuit, C1 = 18.0 nF, C2 = 6.00 nF, C3 = 24.0 nF, C4 = 12.0 nF and
    C5 = 72.0 nF. The energy stored in C5 is 256. nJ.
    Calculate [tex]\epsilon[/tex].

    http://answerboard.cramster.com/answer-board/image/ea6f47d9fdca7dada7592281cfa85c4a.jpg [Broken]

    2. Relevant equations

    q=cv

    3. The attempt at a solution

    C12=24nF
    C34=36nF
    C125=18nF
    C12345=12nF


    q5=q12=q34=(C34)(V34)

    V24=5/36

    V24=0.1389

    lol i donno...can someone help me out. I dont understand this. I know q's are equal in series and V's are equal in parallel but then i get stuck. Please help


    Thanks
     
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Apr 16, 2008 #2

    Redbelly98

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    Staff Emeritus
    Science Advisor
    Homework Helper

    You did well to combine C1&C2, and C3&C4. I think I would not further combine the capacitors, given the specific information given about C5.

    Also, here's another relevant equation:
    (Energy stored) = (1/2) C V^2
     
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