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Homework Help: Rotating Square Loop in Constant B-field

  1. Apr 21, 2012 #1
    [SOLVED] Rotating Square Loop in Constant B-field

    1. The problem statement, all variables and given/known data
    2. Relevant equations

    [itex]\epsilon[/itex] = - [itex]\frac{d\Phi}{dt}[/itex]

    [itex]\Phi[/itex] = BAcos([itex]\theta[/itex]) = BAcos([itex]\omega[/itex]t)

    [itex]d\Phi[/itex] = -BA[itex]\omega[/itex]sin([itex]\omega[/itex]t)

    3. The attempt at a solution

    I'm trying to study for an exam and I've got this practice question that I can answer but my answer never matches. I keep getting b as an answer and I'm not sure if it's right.

    [itex]\epsilon[/itex] = BAcos([itex]\omega[/itex]t) = (2T)(0.2m)2(10)sin(10t)

    I use t = 2s since it asks for [itex]\theta[/itex] = 20° and I get

    [itex]\epsilon[/itex] = (2T)(0.2m)2(10)sin(20) ≈ 0.27 V

    Am I making a mistake or a wrong assumption anywhere or could it be the answer is incorrectly marked?

    Last edited: Apr 21, 2012
  2. jcsd
  3. Apr 21, 2012 #2
    Using "10" might be fine inside the argument of the sine function, but if you're taking it outside when you take the derivative, you need to convert it to rad/s.
  4. Apr 21, 2012 #3
    Thanks, didn't think of that.
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