Please tell me where do electrons exist before current flows?
Can someone tell me..Are free electrons already there in the wire before current is through it? or something happens to atoms as we switch on the current? Are these free electrons float around before current is passed or they are attached to the atom?
Re: Please tell me where do electrons exist before current flows?
An atom contains electrons which revolves around the nucleus only in a permitted discrete levels called energy levels. At room temperature some electrons reach the conduction band while most of them remains at the valence band. These electrons are always present in the material in the wire but their mobility is low when no voltage difference is applied. And when voltage difference is applied, these electrons starts moving under the electric field created in the wire.