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Homework Help: Kindly pls check my physics answers

  1. Apr 5, 2004 #1
    A circuit breaker is rated for a current of 15 A rms at a voltage of 120 V rms. Answer the following questions:
    All answers must have three significant digits unless otherwise specified.

    1) What is the largest value of I(max) that the breaker can carry? (Unit: A)


    I(max) = 15(rms) / square root of 2
    = 10.6A

    2) What average power can be supplied by this circuit? (Unit: kW)

    P(rms) = I (rms) * V (rms)
    = 1.80 kW

    pls correct me if I was wrong and pls direct me to the right path...
  2. jcsd
  3. Apr 5, 2004 #2
    Argh, stupid me.

    I(max) = 15(rms) / square root of 2 is not correct, it should be:
    I(max) = 15(rms) * square root of 2 if I'm not mistaken.
    Last edited: Apr 5, 2004
  4. Apr 5, 2004 #3
    Hi chen,

    what about the 2nd answer? is it correct?

  5. Apr 5, 2004 #4
    Yes, 1.8kW. By the way, you could have noticed that your first answer is wrong because the maximum current cannot be lower than the average current. :smile:
  6. Apr 5, 2004 #5
    Thanks Chen... I see that now...
    you have a good day
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