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Homework Help: Capacitance equired to store an energy of

  1. Oct 9, 2005 #1
    Hello everyone. The question is:
    What capacitance is required to store an energy of 8 kWh at a potential difference of 600 V?
    \This seems like a simple problem..our professor hasn't went over this yet but i saw in the book. P = U/t; I also saw; U = 1/2CV^2; So they gave me U right? because P = U/t, so U = 8 kWh, i converted this into 8kWsecond, by doing this:
    8kwh x 3600sec = 28800kws; I then used:
    C = (2U)/v^2; C = [2*28800]/(600)^2 = .16 which was wrong, i also tried just using 8, and 8/3600, all didn't work.
  2. jcsd
  3. Oct 10, 2005 #2


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    1 KWH = 1*1000*3600 J = 3.6 x 10^6 J (S.I. Unit of energy)
  4. Oct 10, 2005 #3


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    There is still the KILO in there, which you should convert numerically (hint: 1000:-)
  5. Oct 11, 2005 #4
    Ahhh thank you guys, worked great :)
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