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Homework Help: Average power when capacitor discharges

  1. Jul 5, 2011 #1
    1. The problem statement, all variables and given/known data

    https://wug-s.physics.uiuc.edu/cgi/courses/shell/common/showme.pl?cc/DuPage/Phys1202/summer/homework/Ch-21-DC-Circuits/flashbulb_circuit/light-bulb.jpg [Broken]

    The above shows a simplified circuit for a photographer's flash unit. The circuit consists of a V = 9 V battery, connected to a R = 50 kΩ resistor, a C = 140 μF capcitor and two switches. Initially, the capcitor is uncharged and the two switches are open. To charge the unit, switch S1 is closed. To fire the flash, S2 (which is connected to the camera's shutter) is also closed.

    Assume that capacitor discharges itself in 3.3 μsec. What average power put out by the flashbulb during this time?


    2. The attempt at a solution
    I have tried different power equation but i need to include the time so im doing it completely wrong
     
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Jul 5, 2011 #2
    nvm i figured it out
    U=(1/2)CV^2
    P=V/T
    answer was 1718.1818
     
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