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Homework Help: Solenoid question

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

    Find the field and direction inside a pair of coaxial coils. The inner coil carries 3.0A, has 500 loops and is 10cm long. The outer coil carries 10A, has 5000 loops and is 10cm long. Find the field at the center

    Thats the questions, now I don't have trouble working out the numbers (At least I hope I don't). But what I'm wondering is, in the questions, the currents are going in opposite directions, one CW, one CCW. So does that mean that at the end I just subtract them?? or does that not work??

    I got, the 3.0A coil creates 0.0188T. And the 10A coil creates 0.628T. So thats ~=0.61T. I hope thats right. lol
    Last edited: Jan 3, 2008
  2. jcsd
  3. Jan 3, 2008 #2


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    Yes, if the currents are in opposite directions, then you subtract them. It looks ok to me.
  4. Jan 3, 2008 #3
    hey thanks a bunch.
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