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Homework Help: High School Electromagnetism

  1. May 31, 2010 #1
    1. The problem statement, all variables and given/known data

    A 20 turn wire that has a surface of 400cm^2 is rotating around an axe and is at a right angle to a uniform magnetic field of 0.3T. Find the average magnetic field induced if the speed of the rotation is 10 rotations/second.


    2. Relevant equations

    Faraday's Law


    3. The attempt at a solution

    A = 400cm^2 = 0.04m^2
    N = 20
    B = 0.3T
    f = 10Hz



    V =(Nxdelta phi)/delta t
    B = phi/A
    phi = BA = 0.3x0.04 = 0.012wb
    V= (20x0.012)/0.1 = 2.4 Volts


    Answer = 9.6 V

    Can anyone point out where my error is? If there isnt any its possible the answer is wrong.
     
  2. jcsd
  3. May 31, 2010 #2

    rock.freak667

    User Avatar
    Homework Helper

    you did not include the rotational speed

    E=d/dt(NBAcostωt)

    remember θ=ωt
     
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