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Homework Help: Final Voltage

  1. Oct 1, 2009 #1
    1. The problem statement, all variables and given/known data

    Two capacitors of 34.0 μF and 125 μF are separately charged to 126 μC and 250 μC, respectively. They are then attached in parallel so that the + plate of one goes to the - plate of the other, and vice versa. Determine the final voltage across the two plates.

    2. Relevant equations


    3. The attempt at a solution

    I calculated the change in voltage by adding Q1 and Q2 and then dividing by the sum of C1 and C2. (126+250)/(34+125)=2.36 V. How do I find the initial voltage so that I can get the final voltage?
  2. jcsd
  3. Oct 1, 2009 #2


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    Homework Helper
    Gold Member

    Note how the 2 caps are attached to each other. "Initial voltage" does not seem like a relevant concept.
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