Question

When there is an electric current through a conducting wire along its length then electric field must be?

Answer 1

If the conductor has zero resistance, then the force required in order to sustain the current is zero, (the electrons keep moving by themselves) so yes, the electric field is zero. ... Hence, no electric field, no current.

Answer 2

when there is an electric current through a conducting wire along its length then electric field must be at a point is found by biot-savart's law.

B = uidlsin@/4πr^2