Find the Electric Field strength

[Zorba]

Homework Statement

"A copper cable carrying 50A current has radius 0.003m. What is the electric field if copper has a resistivity of 1.7x10^-8 Ohm/m?"

Homework Equations

Formula for current density etc.

The Attempt at a Solution

So I write:
\vec{\mathbf{J}} = n|q|v_d = \frac{I}{A}

And then:
\vec{\mathbf{J}} \cdot \rho = \frac{I}{A} \cdot \frac{RA}{L} = \frac{V}{L}

And now do I just apply the work energy theorem?:
\int \vec{\mathbf{E}} \cdot d\vec{\mathbf{l}} = \Delta V_{ab}

It kind of feels as though I'm completely off tbh...

 

[Cyosis]

Use Ohm's law \mathbf{J}=\sigma \mathbf{E}.