# Energy dissipated from a wire

1. Feb 23, 2008

### 743344

1. The problem statement, all variables and given/known data

Two 10-cm-diameter metal plates are 1.0 cm apart. They are charged to \pm12.5 nC. They are suddenly connected together by a 0.224-mm-diameter copper wire stretched taut from the center of one plate to the center of the other.

a) What is the maximum current in the wire?
b) What is the largest electric field in the wire?
c) What is the total amount of energy dissipated in the wire?

2. Relevant equations

3. The attempt at a solution
i already got part a an b.. the answers are 4.17×10^5 A and 1.80×10^5 V/m , respectively

part c........i can't figure it out......how to calculate the energy?
help

i think the energy dissipated from the wire goes to the capacitor

2. Feb 23, 2008

### dlgoff

What would be the force exerted by the e-field on a point charge of q? Now how is work and hence potential energy related to this force?

3. Feb 23, 2008

### 743344

what is the charge on the point charge

F = qE
W = Fdcos(angle)

W = qEd
U(electric potential energy ) = - W(electric)
then
U = -qEd