If you take a perfect conductor, there cannot be a field across it since if there were, the particles would arrange themselves in a way to cancel out the field right?
Yet, why does the same not hold true for a wire. A wire is essentially a long, thin conductor yet electrons do indeed flow so there must be an electric field.
Does this not contradict with what happens in a conductor? Why don't the electrons re-arrange to cancel out the electric field?
Answer
The electric field in a conductor is zero if the charges are not moving. The electrons do re-arrange themselves to (try to) cancel out the electric field. That is what is happening in an electric wire; there is no contradiction.
The difference between an electric wire that is part of an electric circuit and the same wire isolated in space (when there would be no static electric field inside it) is that there is a source of EMF in the former case which is taking charge from one end of the wire and putting it in at the other end.
No comments:
Post a Comment