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Homework Help: Electric Generators and Faraday's Law

  1. Nov 3, 2013 #1
    1. The problem statement, all variables and given/known data
    When a generator turns at 60 Hz, the amplitude of the induced EMF is 50 V. What is its amplitude when it turns at 180 Hz if the magnetic field remains the same?

    2. Relevant equations
    ω = 2∏f

    ε = ε0sin ωt

    3. The attempt at a solution

    If f = 180 Hz,

    ω = 2∏(180 Hz)

    ω = 1131 m/s

    To find ε0 at 180 Hz:

    ε/sin ωt = ε0

    From this I get:

    (50 V) / sin(1131 m/s)

    ε0 = 64.3 V

    However my book says that the answer should be 150 V and I'm not sure what I did wrong with it...
  2. jcsd
  3. Nov 3, 2013 #2
    50V is ε0.
    ε0 = NABω. NAB doesn't change.

    Solve for NAB and use that value to solve for the new ε0.
  4. Nov 3, 2013 #3
    Thank you so much!!! Figured it out! :biggrin:
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