Electrical Engineering ⇒ Topic : Conductor

conductor 

A substance which has a large number of free electrons at room temperature is called a conductor of electricity e.g. all metals. If a voltage source (e.g. a cell) is applied across the wire of a conductor material, free electrons readily flow through the wire, thus constituting electric current.The best conductors are silver, copper and gold in that order. Since copper is the least expensive out of these materials, it is widely used in electrical and electronic industries