Question

To move charges in metallic wires, an internal electric field must exist in the wire.In such a wire, are the electric field and the electric current in the same or opposite directions? WHY?

Answer 1

The electric field and the electric current both have the same direction. This is because, when an electron is kept in electric field, it experiences a force of magnitude -

F = E / q

Where F is the magnitude of force acting on the electron, E is the magnitude of electric field and q is the charge of an electron.

Now charge q on the electron is negative so direction of force F is opposite to the direction of E.

Again, direction of current is opposite to the direction of motion of the electron. Therefore, the direction of current and the direction of electric field are the same.