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Calculating Q (dot)

  1. Dec 9, 2008 #1

    Wondering if someone could help me satisfy my curiosity. Hopefully a very simple for someone who knows. I have been given values for Voltage and Current. To calculate Q (dot), I know Q(dot)=V * A. The units for this are Watts / J/s / Nm/s.. How can Voltage multiplied by a current provide these units?


  2. jcsd
  3. Dec 9, 2008 #2


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    Welcome to PF!

    Hi William! Welcome to PF! :smile:

    From electric units in the PF Library

    Power = voltage.current = energy/time (dim. [itex]ML^2/T^3[/itex]):

    [tex]\text{W}\ \equiv\ \text{watt}\ \equiv\ \frac{\text{J}}{\text{s}}\ \equiv\ \frac{\text{joule}}{\text{second}}\ \equiv\ \frac{\text{N.m}}{\text{s}}\ \equiv\ \frac{\text{newton.metre}}{\text{second}}\ \equiv\ \text{V.A}\ \equiv\ \text{volt.amp}\ \equiv\ \Omega\text{.A}^2\ \equiv\ \text{ohm.amp}^2[/tex]
  4. Dec 9, 2008 #3
    Thank you very much. Good to of joined.

    Thats that sorted then, thanks for clearing up.

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