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Homework Help: A.C. Circuit

  1. May 2, 2006 #1
    An electric toaster draws 3A rms current from a 240V, 50Hz source. Calculate the average power and peak value of the instantaneous power to the toaster.

    [tex] P(average) = I (rms) x V (rms) cos \phi [/tex]

    Since the power factor is not mentioned in the question. Can the question be solved?
     
  2. jcsd
  3. May 2, 2006 #2

    berkeman

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    Staff: Mentor

    If the power factor isn't given, it probably isn't needed. What would you guess the power factor of a toaster to be? What is the heating mechanism?
     
  4. May 2, 2006 #3
    Is it because all the energy become heat so the power factor is equal to one ?
     
  5. May 2, 2006 #4

    berkeman

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    Staff: Mentor

    Yeah. The heating element is purely resistive, and the power factor of a resistive circuit is unity. You only get a phase shift between the applied voltage and resulting current if the load is reactive.
     
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