Electric field density at the surface of a current carring wire

[cuttlefish]

Homework Statement

Calculate the magnetic and electric energy densities at the surface of a 3.0 mm diameter copper wire carrying a 15-A current

Homework Equations

u_B=.5\frac{B²}{\mu₀}
u_E=.5\epsilon₀E²
R=\rho(L/A)
B=(\mu₀I)/(2\pir)
\rho=1.68 x 10^-8 ohm-meters

The Attempt at a Solution

Okay, so finding the magnetic energy density isn't too difficult. My problem is with the electric energy density. I can use the area of the wire and the fact that it's copper to find the resistance and then use ohm's law to find the voltage. but then I get in this bind. E=V/d, but at the surface of the wire, d=0 so you get V/0 which kind of implies infinity and this agrees with my thoughts anyway. However, I feel like this doesn't really make any sense in terms of an electric energy density. Does some one see where the reasoning is going wrong and how I can make it right?

 

[cuttlefish]

whoa...okay the equations got screwed up there. Hope you can understand them...B^2 is obviously the one in magnetic energy density, mu sub zero, E^2. Sorry about that folks.

 

[cuttlefish]

I've just realized that the same problem comes up with my magnetic field. So. Basically I have no idea what I'm doing and am in need of desperate help.