# Faraday's Law of Electromagnetic Induction

1. May 8, 2006

### spoonthrower

A magnetic field is perpendicular to a 0.060 m 0.060 m rectangular coil of wire that has 100 turns. In a time of 0.070 s, an average emf of magnitude 1.5 V is induced in the coil. What is the magnitude of the change in the magnetic field?

My professor has not covered this in lecture yet, but this HW is due tomorrow. Reading the section for myself and looking at the equations, this is what i have come up with so far. Please help me out, thanks.

average induced emf=magnetic flux/time

average induced emf=B(Area)/time

average induced emf=-N(magnetic flux)/Time

Where do i start?????

2. May 8, 2006

### Staff: Mentor

You're on the right track in applying Faraday's law, which relates the induced EMF to the rate of change of the magnetic flux. The flux through each loop equals B*Area; since the area is constant, the change in flux equals Area*(change in B).

Assume that the field increases uniformly and you can calculate the change in B; everything else is given.

3. May 8, 2006

### spoonthrower

got it. thanks.