The magnetic field between the poles of an electromagnet is 2.6 T. A coil of wire is placed in this region so that the field is parallel to the axis of the coil. The coil has electrical resistance 25 , radius 1.9 cm, and length 15.0 cm. When the current supply to the electromagnet is shut off, the total charge that flows through the coil is 7.0 mC. How many turns are there in the coil?(adsbygoogle = window.adsbygoogle || []).push({});

I know that I have to use more than one equation but I've searched through my book for a couple hours now and nothing is helping. So far, I've picked up these equations:

I = (epsilon)/R = vBL/R

(epsilon) = -L (deltaI / deltat)

L = (mu0) n^2 (pi) r^2 l

flux = LI = (mu0) N I (pi) r^2

I tried to combine the equation for epsilon and self inductance (L) and came out with the wrong answers of 3.42E5 and 5.13E4. Ridiculously large numbers I'm sure. I would appreciate any insight =)

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# Homework Help: Comprehensive electromagnetic induction question

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