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NoPhysicsGenius
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Homework Statement
The following is Problem 1-13 on page 23 from Electrical Engineering Fundamentals, 2nd ed., by Vincent del Toro:
"In the configuration shown in Fig. P1-13 the coil has 100 turns and is attached to the rotating member which revolves at 25 \frac{rev}{s}. The magnetic flux is a radial uniform field and has a value of \phi = 0.002 weber (Wb). Compute the emf induced in the coil."
Here is Fig. P1-13 ...
http://www.flickr.com/photos/jjhobson/8005932239/in/photostream
Homework Equations
e = - \frac{d\lambda}{dt} = -N\frac{d\phi}{dt}
Note that e stands for emf (or electromotive force), \lambda stands for the flux linkage in weber-turns, N stands for the number of turns in the coil, and \phi stands for the magnetic flux.
The Attempt at a Solution
First of all, the answer given in the back of the book is 20 Volts.
e = -N\frac{d\phi}{dt} = -(100)\frac{d\phi}{dt}
\Rightarrow \frac{d\phi}{dt} = -\frac{e}{100}
\Rightarrow d\phi = -\frac{e}{100}dt
\Rightarrow \phi = -\frac{1}{100}\int e dt = 0.002 Wb
\Rightarrow \int e dt = -0.2 Wb
Unfortunately, I don't know where to go from here. Also, I don't know where the 25 rev/s quantity comes into play.
Any help would be greatly appreciated. Thank you.