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Homework Help: Energy of capacitor and work

  1. Jan 10, 2006 #1
    The capacitor of capacitance C is charged by battery (emf = E) (assume that there is no resistance). In the end charge of the capacitor Q = C*E; Work done by the battery W = Q*E=C*E^2. But The energy of charged capacitor is U = (C*E^2)/2. Work doesn't equals to stored energy. Where we lost energy?? Can we forget about kinetic energy of the charges it this case?? Or it is exactly that "lost" energy?
  2. jcsd
  3. Jan 10, 2006 #2


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    Staff: Mentor

  4. Jan 10, 2006 #3
    Thank you very much. As i understood, the model without resistance isn't realy physical. With nonzero resistance everything is ok.
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