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Homework Help: Electric Capacitators 1

  1. Feb 10, 2009 #1
    1. The problem statement, all variables and given/known data

    A capacitor is in this device is charged 6.10KV and stores 1140 J of energy. What's the capacitance?

    2. Relevant equations
    W= 1/2 Q Delta V

    3. The attempt at a solution
    PE is W
    W= 1140 J
    Delta V: 6.10 KV
    Q =?

    Delta V = -W/Q rewrite to Q= -W/Delta V
    convert kV to V
    Q= -1140/6100V= -.18

    then C= Q/V -.18/6100= -3.06E -5
  2. jcsd
  3. Feb 10, 2009 #2
    Inasmuch as you're given energy (Joules) would you happen to know a formula for finding capacitance from voltage and energy? (hint: The formula is usually written for finding energy from voltage and capacitance.)
  4. Feb 10, 2009 #3
    if C= Q/V is what your saying, C and Q isnt given in this case there only V.
  5. Feb 10, 2009 #4


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