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Homework Help: Magnetic Force on a Conductor

  1. May 26, 2007 #1
    1. The problem statement, all variables and given/known data
    I am conceptualizing for a high school physics project and what I am currently trying to do is setup two ceramic magnets with opposite poles facing each other, but with a space in between. Next I have a wire running in between that is connected to a 1.5V power supply consisting of four AAA zinc chloride batteries in parallel. The wire is supposed to jump according to the right hand rule, however when I activate the on switch in the battery holder, nothing happens on a visible level. The connections are fine since I have tested it on a light bulb

    2. Relevant equations

    3. The attempt at a solution
    This is the tricky part since I am missing some definite numerical data. I assume that the force generated is very small.
    What I do know:
    The wire is perpendicular to the magnets so sinθ=1. The length of the wire is close to 1m.

    What I don't know:
    The magnets are small ceramic magnets (12mm in diameter, and 4mm and 6mm in height), of decent strength for their size, but no numerical info about their field strength was provided during purchase. So the value of B is missing, but can be found out through a kinetics based investigation. I would have to weigh the magnets though, and currently don't have access to a precise balance.

    I have searched online for info on the current produced by AAA batteries to no avail. Most sites are providing mA hours, and I can't derive a current from that without knowing the hours. However I am guessing the current is too weak.

    I am hoping some experienced people can know what is generally required for this experiment. Would there be a problem if the wire is insulated? Or what if the conducting threads were wound in a spiral or helix like formation... would that effect the angle? Thanks.
  2. jcsd
  3. May 27, 2007 #2
    OK, I have determined that the current is approx 0.086 Amps and that it was the static friction of the wire on the wood surface that prevented movement. When I let the wire hang, there was a notable force. I would still liked to know if insulation around wires reduce the magnetic fields created by currents moving through the wires.
  4. May 27, 2007 #3
    When I saw this experiment done it was done with a HUGE wire, I am talking 1/2" thick, and the magnet was huge. Current was dangerously high as well(300A), the wire got hot fast. I wouldn't suggest trying it. (in fact you would be crazy if you tried it)
    Last edited: May 27, 2007
  5. May 27, 2007 #4
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