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Average induced EMF

  1. Feb 28, 2010 #1
    1. The problem statement, all variables and given/known data

    The area of a 100 turn coil oriented with its plane perpendicular to a 0.28 T magnetic field is 4.3×10−2 m^2.
    Find the average induced emf in this coil if the magnetic field reverses its direction in 0.36 s.

    2. Relevant equations

    E = -N (flux - flux initial)/(t-to)

    3. The attempt at a solution
    I'm actually not even sure I am using the correct equation. It is the only one I see that uses N. But I'm not sure how I would find an initial time and even a flux. Help?
     
  2. jcsd
  3. Feb 28, 2010 #2

    kuruman

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    It is the correct formula.
    Look up the definition of flux.
    Note that the denominator is t - t0. How does "... reverses its direction in 0.36 s" relate to t - t0?
     
  4. Feb 28, 2010 #3
    ok i found something in which i can use BAcostheta instead of flux... would that work? and i guess t would be 36 and initial would be zero?
     
  5. Feb 28, 2010 #4

    kuruman

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    Correct on both accounts. What is cos(theta) here?
     
  6. Mar 1, 2010 #5
    is it just 1?
     
  7. Mar 1, 2010 #6
    also would A stay the same? and how to find B? or do you have to find B initial?
     
  8. Mar 1, 2010 #7

    kuruman

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    Yes.
    A stays the same. As for B, read the problem carefully; Binitial and Bfinal are both given to you.
     
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