Electric field inside a conducting wire

[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?
The answer is I=4.65A.

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 "

 

[cnh1995]

according to Gauss law, the electric field inside the conductor is zero

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.

 

[Dale]

according to Gauss law, the electric field inside the conductor is zero

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.

 

[Mohammed Shoaib]

Thanks a lot for clearing my confusion.