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Homework Help: Magnetic Field vectors

  1. May 1, 2005 #1
    I have racked my brain for the past two hours and I can't figure this out. If any one can help me with, please do.

    Two long parallel wires 6.00 cm apart carry 19.5 A currents in the same direction. Determine the magnetic field strength at a point 12.0 cm from one wire and 13.4 cm from the other. (Hint: Make a drawing in a plane containing the field lines, and recall the rules for vector addition.)

    I found the magnetic field for each of the wires seperately using B = Mo(I)/ r

    but I cannot understand what the "vectors" have to do with the problem.
  2. jcsd
  3. May 1, 2005 #2

    Doc Al

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    Staff: Mentor

    The magnetic field is a vector: direction matters! The magnitude of the magnetic field surrounding a long, current-carrying wire is [tex]B = \frac{\mu_0 I}{2 \pi r}[/tex]; the direction is given by the right-hand rule.

    The first thing to do is draw a careful diagram so you can figure out the directions of each contribution to the magnetic field. Add them (as vectors, of course) to get the total field at that point.
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