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Homework Help: Parallel-plate capacitor charge problem

  1. Feb 12, 2010 #1
    1. The problem statement, all variables and given/known data
    Two 10.0 -diameter electrodes 0.56 apart form a parallel-plate capacitor. The electrodes are attached by metal wires to the terminals of a 14 battery. After a long time, the capacitor is disconnected from the battery but is not discharged.
    a. What is the charge on each right after the battery is disconnect? What is q1, q2 in coulombs

    2. Relevant equations

    3. The attempt at a solution I have tried several attempts, but still have the answer 1.74*10^-10. What have I done wrong.
  2. jcsd
  3. Feb 12, 2010 #2
    This is how I did the work.
    pi*.01/4=.007853982*8.85418/.0056=12.42*10^-12*14=1.74*10^-10, 1.7*10^-10 Answer in 2 significant digit?
  4. Feb 14, 2010 #3


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    Staff Emeritus
    Science Advisor

    Is one saying that 1.7*10^-10 is the answer?

    1.74*10^-10 in two significant digits would be 1.7*10^-10.

    It would also help if one provides units. I would guess the capacitor plates have a 10 cm dia, and are 0.56 cm apart?

    Also, please write all the equations. Please see - http://hyperphysics.phy-astr.gsu.edu/hbase/electric/capac.html
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