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Potential difference between plates

  1. Jul 12, 2008 #1
    1. The problem statement, all variables and given/known data
    he electronic flash attachment for a camera contains a capacitor for storing the energy used to produce the flash. In one such unit, the potential difference between the plates of a 705 µF capacitor is 320 V.

    (a) Determine the energy that is used to produce the flash in this unit. _____J
    (b) Assuming that the flash lasts for 5.0 multiplied by 10-3 s, find the effective power or "wattage" of the flash. _______W


    2. Relevant equations
    Energy=1/2CV^2


    3. The attempt at a solution
    .5(7.05 x 10^-6 F)(320V)^2. this gave me .3606, which was not the correcct answer for part A
     
  2. jcsd
  3. Jul 12, 2008 #2

    Doc Al

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    Staff: Mentor

    Is the capacitance 705 µF or 7.05 µF?
     
  4. Jul 12, 2008 #3
    it's 705 uF. i thought i was supposed to convert uF to F. (1F=10^-6uf?)
     
  5. Jul 12, 2008 #4

    Doc Al

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    Staff: Mentor

    Right. But you also "converted" 705 to 7.05 for some reason. :wink:
     
  6. Jul 12, 2008 #5
    ohhh i see. so (705 x 10^-6)*(302)^2=36.096?
     
  7. Jul 13, 2008 #6

    Defennder

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    Homework Helper

    Yet another typo. Is it 302 V or 320 V?
     
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