Electrical energy dissipated in resistance of a wire

[osugirl10]

Homework Statement

A piece of copper wire is formed into a single circular loop of radius 10 cm. A magnetic field is oriented parallel to the normal to the loop, and it increases from 0 to 0.70 T in a time of 0.45 s. The wire has a resistance per unit length of 3.3 10-2 /m. What is the average electrical energy dissipated in the resistance of the wire.

Homework Equations

Emf = -NAB/t
P = V(^2)/R
E = Pt

The Attempt at a Solution

I used The first equation to find emf... -.0489V
with that I plugged it into the second equation (for R I took my resistance per unit length times the circumference of my circle - pi*d)
so for my power I got .0489^2/.0207 = .1155
Then I thought I would just plug that number into the third equation
E = .1155w(.45s)
which would give me .052 J
but this isn't the right answer.
Where did I go wrong?

 

[gneill]

The method and numbers look okay to me.