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Homework Help: Quick emf problem

  1. Sep 25, 2005 #1
    Here is the question. A coil rotates at 200 revoltuions per second in teh earth's field. If the coil has a cross sectional area of 20cm^2 and has 1000 turns, approximately what emf is induced in the coil as a function of time?

    I know emf= int of E*dL and that the voltage proudces across a coil is V= NwBA sin(wt). I guess what i don't get is what would i use for my B or do i need to use a different equation.
  2. jcsd
  3. Sep 26, 2005 #2
  4. Sep 26, 2005 #3
    Unless I'm mistsaken, the B in the statement here is the earth's B. The Value for earth is .5 Gauss, an extremely weak number compared to the tesla. find a conversion factor to get that value in tesla and there's your B value. now remember, the voltage is also written as v=vmaxsin(omega t). V max is dependent abviously on your B field, you number of turns and so on. If you need more help or if that wasn't suficient, then let me know
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