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Joule's law and power

  1. Apr 14, 2010 #1
    Hello, i want to ask 2 questions:
    1-what is the difference between joule's heat and power?
    2-We have 2 different resistors.How joule's heat ,which is created in them, will change if they connect to a steady voltage source:(a)in series,(b)in parallel
    Thank you
     
  2. jcsd
  3. Apr 14, 2010 #2

    rock.freak667

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    What are your thoughts on the subject?

    Is Joule's heat just energy or something else? How does energy relate to power?


    Also, how is total resistance affected when resistors are in series/parallel?
     
  4. Apr 14, 2010 #3
    total resistance in series is Rt=R1+R2+....+Rn and in parallel 1/Rt=1/R1+1/R2+...+1/Rn.
    Joule's law sais Q=I^2*R*t where Q the heat generated by a constant current.If (I) and (t) are constant Q is proportionate to R so in series Q will increase more than when the resistors are in parallel.Correct?
     
  5. Apr 14, 2010 #4

    rock.freak667

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    Wouldn't the total resistance in parallel be less than in series?
     
  6. Apr 14, 2010 #5
    thats what i said
     
  7. Apr 14, 2010 #6

    rock.freak667

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    Sorry I read that incorrectly. But you are correct.

    and remember that power is the rate of change of energy.
     
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