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Average Potential Difference

  1. Apr 22, 2008 #1
    [SOLVED] Average Potential Difference

    1. The problem statement, all variables and given/known data
    The voltage across the terminals of an ac power supply varies with time according to V=V_0\cos(\omega t). The voltage amplitude is V_0 = 46.0 V

    From the prior question, I already figured out that the root-mean-square potential difference is 32.5. V

    Question What is the average potential difference V_{{\rm a}{\rm v}} between the two terminals of the power supply?


    2. Relevant equations

    [tex]V_{rms}=V/\sqrt{2}[/tex]
    [tex]V_{rms}=Vcos(\omega*t+\varphi)[/tex]


    3. The attempt at a solution

    At first I thought that the average and the rms was the same thing, but now I can't figure it out. Does it involve finding current?
     
  2. jcsd
  3. Apr 22, 2008 #2
    The average is just like the rms, except you don't square before integrating and you do not take a square root afterwards. It does noet involve finding current
     
  4. Apr 22, 2008 #3
    Hm, I don't understand. Where would you be integrating?
     
  5. Apr 22, 2008 #4
    when calculating the average. How did you calculate V_rms? You integrate over one full period of the AC and divide by the length of the period.
     
  6. Apr 22, 2008 #5
    All I did to calculate V_rms was taking V divided by square root of 2, since for any sinusoidally varying quantity the rms value is always [tex]\frac{1}{\sqrt{2}}[/tex] the value. I didn't integrate at all.
     
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