Fine wire is often sold by the pound, rather than length. You read that the length of a pound of $30-$gauge round copper wire is $3200$ ft $.$ What is the resistance of the wire? The resistivity of copper is $1\mathrm{.}67{10}^{-8}*m,$ its density is $8960k\frac{g}{m^3}.$

A closely wound rectangular coil of $50$ turns has dimensions of $12$ cm by $25$ cm $.$ The plane of the coil is rotated from a position where it makes an angle of $45$ with a magnetic fleld of $2\mathrm{.}0$ T to a position perpendicular to the field in a time $t=1\mathrm{.}0s.$ What is the average emf induced in the coil?