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Homework Help: Lenz's Law and EMF wire

  1. Mar 11, 2008 #1
    1. The problem statement, all variables and given/known data
    A wire is bent into three circular segments each of radius r=9.2 cm. each segment is a quadrant of circle, ab lying in the xy plane, bc, in the yz plane, and ca lying in the zx plane. If a uniform magnetic field points in the positive x direction, what is in volts the magnitude of the emf developed in the wire when B increases at the rate of 3.4 mT/s?
    http://edugen.wiley.com/edugen/courses/crs1141/art/images/c31/nw0500-n.gif


    2. Relevant equations
    so what i used was faraday's law and lenz's law by using the formula
    [tex]\epsilon[/tex]=d(B A)/dt
    and then since area (A) is constant you can bring it out. and area would equal 1/4[tex]\pi[/tex]r[tex]^{2}[/tex] and the dB/dt is given. the only problem is that i dont know what to do with the components as you have the pieces on all three axis and how wood i deal with each component?
     
  2. jcsd
  3. Mar 12, 2008 #2

    pam

    User Avatar

    There are no components for the EMF. Your projected area seems right.
    Just multiply A and dB/dt.
     
  4. Mar 12, 2008 #3
    oh so jus do it for each section and add it up or make it 3/4pi*r^2 time dB/dt
     
  5. Mar 12, 2008 #4

    pam

    User Avatar

    No. The projected area area for the flux is just the pi*r^2/4.
     
  6. Mar 12, 2008 #5
    oh ok thanks alot
     
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