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Homework Help: Inductive reactance and length of the solenoid

  1. Nov 1, 2009 #1
    1. The problem statement, all variables and given/known data
    A solenoid with a radius of 8.0 10-3 m and 170 turns/cm is used as an inductor in a circuit. When the solenoid is connected to a source of 15 V rms at 22 kHz, an rms current of 3.7 10-2 A is measured. Assume the resistance of the solenoid is negligible.
    (a) What is the inductive reactance?
    (b) What is the length of the solenoid?

    r = 8E-3 m
    n = 170E2 turns/m
    Vrms = 15 V
    f = 22E3 Hz
    Irms = 3.7E-2 A
    Area = pir^2 = 2.01E-4 m^2

    2. Relevant equations
    XL = 2pifL

    L = μn^2pir^2l

    3. The attempt at a solution
    I know how to utilize the equations, but my problem is finding L (self-inductance) in order to solve both part a and b. I try looking throughout my physics book, but nothing.

    a) XL = 2*pi*22E3*L

    b) L = 4piE-7*17000^2*3.14*8E-3*l
  2. jcsd
  3. Nov 1, 2009 #2
    Nevermind, I managed to figure the problem out myself.
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