Electric current by name it is clear that it is the rate of flow of electric charge past a region and an electric current is said to exist where there is a flow of net or electric charge through a region. Ampere is the SI unit of electric current and it is measured by using a device called an ammeter. Electric current causes Joule heating which creates light and which also creates magnetic fields that are used in motors, inductors, and generators. Charge carriers are the moving charged particles in an electric current and in metals; one or more electrons from each atom are loosely bound to that atom so that these conduction, in other words, these electrons are the charge carriers in metal conductors. There is a symbol for the current which is denoted by I which is known as intensity and it is also referred to current also. A flow of positive charges gives the same electric current and have the same effect in the circuit.
How the flow of electric charges in the metallic conductor and drift velocity?
This is a fact that metals are a great conductor of heat as well as electricity some of the metals are used for wiring as they are the best conductor of electric current as in metals some of the outer electrons are not bound from the atom as they are insulating material but they are free to move within the metal lattice. For example, if we take a battery in which metal wire is connected across the two terminals of a direct charged voltage source in which the source places an electric field across the conductor. Drift velocity is the average velocity attained by charged particles like electrons, due to the electric field. In other words, drift velocity is proportional to the current or in a resistive material it is also proportional to the magnitude of the external electric field.
What are mobility and their relation with the electric current?
Mobility of electric current is the ability of charged particles which are known as electrons and protons which move through a medium in response to an electric field that is pulling them. There is a term called mobility spectrometry which includes separation of ions according to their mobility which is in the gas phase. In other terms or in other words, this phase of gas mobility is also known as electrophoresis.