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Looking for capacitive reactance but missing "C"

  1. Jul 22, 2014 #1
    1. Current and voltage graphs are shown for a capacitor circuit with ƒ=1000Hz.
    What is the capacitive reactance Xc?




    2. I know the equation is Xc= 1/2∏ƒC to solve for capacitive reactance but where do I find C? All of our in class examples had C and ƒ given.



    3. The attempt at a solution
     

    Attached Files:

  2. jcsd
  3. Jul 22, 2014 #2

    NascentOxygen

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    That formula is not correct. You need a pair of brackets to set it right or you'll never get the right answer!

    What would be the equation for current if you connect that capacitance C to an AC voltage source V volts?
     
  4. Jul 22, 2014 #3

    SammyS

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    Get the reactance from the graph.


    What are peak voltage & peak current?
     
  5. Jul 22, 2014 #4
    The only other thing I can think to do is rearrange ΔVc= I*Xc

    Xc= ΔVc/I
    Xc= 10V/10x10^-2 A which gives me 100Ω
     
  6. Jul 23, 2014 #5

    NascentOxygen

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    10V looks right for the voltage. But that's not the right way to write 10mA.
     
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