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Homework Help: Parallel wires and forces acting upon them

  1. Apr 10, 2012 #1
    Two long, parallel wires are separated by a distance of 1.0 m. The current in each wire is 1.0 A.
    Which of the following is the magnitude of the force on 1.0 m length of each wire?
    A. 2π×107 N
    B. 2×107 N
    C. 2π×10–7 N
    D. 2×10–7 N

    2. Relevant equations
    Force on wire= B field density * Length of wire * Current flowing through it

    Hi! This problem came up in one of my practice tests and it completely eludes me. I know the answer is D, but the markscheme offers no explanation. I'm certain the answer has to do with magnetic fields that arise due to current flowing through the wires but I cannot think myself past this simple stage. I'll be extremely thankful for any helpful explanation!
  2. jcsd
  3. Apr 10, 2012 #2
    each wire creates a magnetic field B. Do you know how to calculate B at a distance from a straight wire?
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