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Homework Help: The current in a solenoid

  1. Apr 23, 2012 #1
    1. The problem statement, all variables and given/known data

    A solenoid is 0.16 m long and consists of 130 turns of wire. At its center, the solenoid produces a magnetic field with a strength of 2.0 mT. Find the current in the coil.

    2. Relevant equations
    B=μNI/L B=strengh of magnet N=number of loops I= current and L=lengh μ is the constant 2e-7

    3. The attempt at a solution
    I plugged in 2mT=(2e-7)(130)(I)/.16m
    I got 2mt=(.0001625)(I). I then did 2/.0001625 and got the current to equal 12,307.69 but it isn't right.What did I do wrong?
  2. jcsd
  3. Apr 23, 2012 #2


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    Homework Helper

    hi tomsolo, and welcome to physicsforums :)
    Ah, it looks almost correct, but there are two things that I'm not sure about. Why is μ equal to 2E-7 ? In free space it is roughly equal to 13E-7 Also, on the last line, you've got 12,307.69 but you still need to take into account that the magnetic field was in milliTesla.
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