# Homework Help: Electromagnetic Induction

1. Mar 14, 2005

### rocky811

I'm having some trouble with these two problems.

1.
A 1.2-m-long aluminum rod is rotating about an axis that is perpendicular to one end. A 0.16-T magnetic field is directed parallel to the axis. The rod rotates through one-fourth of a circle in 0.65 s. What is the magnitude of the average emf generated between the ends of the rod during this time?
THis one i wasn't sure either but i tried using the -N times the flux/time..but i wasn't sure if that was the right equation either.

2.
A piece of copper wire is formed into a single circular loop of radius 14 cm. A magnetic field is oriented parallel to the normal to the loop, and it increases from 0 to 0.56 T in a time of 0.66 s. The wire has a resistance per unit length of 3.4 x 10-2 /m. What is the average electrical energy dissipated in the resistance of the wire?

For this one I was trying to do emf=BAcostheta/t and then i used that value in the equation P=V^2/R however, i can't get the right answer.