I’ve come across a lot of physics problems which ask of a current carrying wire has an electric field around it or will a current carrying conductor A induce charge on an adjacent grounded conductor B, and everywhere the explanation to the question is that current carrying conductors are electrically neutral. It’s stated like a universal truth everywhere and I can’t understand why does a conductor need to be neutral to carry current? Are there instances of charged conductors carrying currents?
( I understand that bit about electrons of the metal and the positive kernel cancelling each other’s charges. My question is, if I dump some charge on a current carrying wire, will it still carry current?)
I’m in high school, so a simple explanation will be appreciated.
[Physics] Why do current carrying conductors need to be uncharged
chargeconductorselectric-current
Best Answer
They don't. Consider the simple case of a cell (battery) connected, via two conductors, to a resistor.
Though there is a current through the conductors, they are not electrically neutral; the conductor connected to the positive (negative) terminal of the cell has net positive (negative) charge.
As William Beaty explains here, this is necessarily the case since the energy flow from the cell to the resistor implies the existence of both an electric and magnetic field along the length of the conductor such that there is a non-zero Poynting field.
From the linked Wikipedia article:
Note the dashed electric field lines between the conductors.