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Homework Help: RLC circuit

  1. Nov 20, 2008 #1
    1. The problem statement, all variables and given/known data

    A circuit contains only two of the three elements L,C ,R. When connected to a 120 V , 60 HZ ac generator, the current of 6.4 A lags the voltage by 30o. What are the two elements and their values?

    2. Relevant equations

    3. The attempt at a solution

    given E = 120v,
    f = 60Hz,
    i = 6.4A,
    φ =300
    From the problem current lags voltage so this is a circuit containing resistance and inductance
    inthis circuit , tanφ = ωL/R
    R = E/i = 120/6.4 = 18.75Ω
    L = tanφR/ω = tan300*18.75/2*3.14 *60 =0.028 henry

    Is this reasoning correct?
  2. jcsd
  3. Nov 20, 2008 #2


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    Homework Helper

    The technique looks good.

    I get a calculated value of .02869

    I used more digits of pi.
  4. Nov 20, 2008 #3
    Thank you so much for the help!
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