# I Electric field inside a conducting wire

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1. Oct 20, 2016

### Mohammed Shoaib

The electric field in a 2.5mm×2.5mm square aluminum wire is 2.1×10−2 V/m . What is the current in the wire?

But my question is according to Gauss law, the electric field inside the conductor is zero. then how come this question says
"The electric field in a 2.5mm×2.5mm square aluminum wire is 2.1×10−2 V/m "

2. Oct 20, 2016

### cnh1995

This is true only in electrostatic equilibrium. When you connect a voltage source across a conductor, there will be a non-zero electric field inside the conductor and it will drive a current through the conductor such that current density J=σ*E, where σ is the conductivity of the material.

Last edited: Oct 20, 2016
3. Oct 20, 2016

### Staff: Mentor

The response from @cnh1995 is correct, but may have left you wondering if Gauss law is violated. It is not. Gauss's law tells us that if there is no charge inside a surface then the net flux is 0. Inside a conducting wire there is flux, but there is just as much flux going in and going out, so the net flux is zero. Gauss's law holds.

4. Oct 21, 2016

### Mohammed Shoaib

Thanks a lot for clearing my confusion.