# Induced Emf

1. Oct 29, 2008

### Ithryndil

1. The problem statement, all variables and given/known data
A 32 turn circular coil of radius 4.60 cm and resistance 1.00 is placed in a magnetic field directed perpendicular to the plane of the coil. The magnitude of the magnetic field varies in time according to the expression B = 0.0100t + 0.0400t2, where t is in seconds and B is in teslas. Calculate the magnitude of the induced emf in the coil at t = 5.60 s.

2. Relevant equations
$$Emf = -d/dt(NABcos\theta)$$

3. The attempt at a solution

I pulled out the -NAcos(theta) as a constant

-NAcos(theta)d/dt(B)
-NAcos(0)d/dt(0.0100t+0.0400t^2)
-NA(0.0100+0.0800t) where t = 5.6, N = 32 and A = pi*(0.046^2)

The answer I got was: -97.4 mV. I have one submission left and am not sure if that's right considering there is a resistance.

2. Oct 30, 2008

### Ithryndil

Bump, any help is appreciated.