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Homework Help: Magnetic Force

  1. Apr 26, 2005 #1
    Ok, this problem shows up on my test today and I was wondering how you can solve it:

    A circular coil of wire has a diameter of 20 cm and contains 10 loops, internal resistance of 8 ohms, and the coil is placed in a 2.00T external magnetic field. When 1 volt is applied to the coil, determine the maximum force exerted on the coil by the field.

    First of all, I was thinking about using [tex]R = \rho \frac{l}{A}[/tex] and plug in the [tex] l [/tex] into [tex] F = IlB sin \theta [/tex]
    But I wasnt given the [tex]\rho[/tex], so i try the torque formula:[tex]NIABsin\theta[/tex], but end up having Netwon * meter for the unit

    How should i approach this problem?
  2. jcsd
  3. Apr 27, 2005 #2


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    The resistance of the wire is given as 8 ohms. The applied potential is 1 volt. The current is a simple calculation based on this information. After you get that, your appraoch to the magnetism aspects looks reasonable.
  4. Apr 27, 2005 #3
    But how can i solve for [tex] l [/tex] in order to calculate the Force by using [tex]F = I l B sin \theta[/tex] ?
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