How Can an Electric Field Exist in a Conductor with Current Flow?

[sumit6may]

electric field does not exist in conductors because it gets nullified due to polarization of conductor,but in current electricity the electric field is established in a circuit(conductor) which gives drift velocity to electrons for charge flow.how can electric field exist in a circuit?

please help.

 

[jambaugh]

The statement about conductors assumes an idealized continuum conductor. When you resolve at the electron level you get all sorts of E fields moving the electrons around but they in the aggregate will cancel.

Remember the drift velocity has to do with the collisions between electrons. Since they on the average do not accelerate the E fields pushing them in one direction are countered by the repulsions of nearby electrons (and attraction of vacated nuclei).

But that brings up one exception to the rule. If the current is accelerating quickly then there is a slight net E field due to the F=mA for the electrons. Generally this is too small to measure. Trying to accelerate a current gets you a back reacting E field due to inductance. Indeed one can always claim that the mass of the electron comes from a "vacuum inductance" i.e. from the energy of the surrounding E-M field.

 

[Dale]

An electric field certainly can exist in a (non-super) conductor. What cannot exist is an electrostatic field, but when you have current it is by definition not electrostatic.