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Homework Help: Finding turns per meter in a solenoid

  1. Nov 3, 2008 #1
    1. The problem statement, all variables and given/known data

    The magnetic field produced by the solenoid in a magnetic resonance imaging (MRI) system designed for measurements on whole human bodies has a field strength of 4.0 T, and the current in the solenoid is 300 A. What is the number of turns per meter of length of the solenoid?

    Note that the solenoid used to produce the magnetic field in this type of system has a length that is not very long compared to its diameter. Because of this and other design considerations, your answer will be only an approximation.

    2. Relevant equations
    I thought this equation would be especially useful to solve the solenoid(circular loop):
    B= N(4pi times 10^-7)(I) Divided by R and 2
    N= number of turns; R=length in meters; As I result I think N/R= number of turns per a meter. I could be wrong on this though.
    3. The attempt at a solution
    Trying at the solution I plugged in the respective values for B and I and got 42462.8 turns per meter. This answer is wrong though and I have no idea where I went wrong. Any suggestions to steer me the right way?
  2. jcsd
  3. Nov 3, 2008 #2
    I actually found out what I did wrong. Here is the appropriate way to approach this problem B=N(4pi times 10^-7)(I) Plug in I and B and N= turns per meter...
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