# Induced current due to rotating coil

1. Apr 13, 2012

### caljuice

I attached a problem from a practice exam. I'm stuck on part b). Part A, I'm assuming the answer is the standard equation for an infinite current sheet.

How do I find induced current? I can only think of using Emf = NBA*ωsintωt
Where Emf= I/R, but I don't have resistance.

Only other equation I know is K= ρ*ω*r , where ρ is surface charge density, but don't got that either.

Any help on the first step?

EDIT: Thinking now there might have been a table of resistivity for the copper. Then R can be found easily.

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2. Apr 15, 2012

### Redbelly98

Staff Emeritus
Yes, you need the resistivity of copper and the fact that it is 22 gauge wire. On an actual exam, most teachers or professors would supply you with the necessary information to figure out R; it would be very unusual to require students to memorize the resistivity of different materials or the diameters of different wire gauges.

Alternatively, the information could be given as a table of resistance/length (Ω/m) for various gauges of copper wire.