an electric current exists in a region of space when there's a net transfer of charge through a surface from one side to the other side of the region

if a current through a surface varies either with magnitude or direction or bith it is unsteady or varying

one ampere=one coulomb of charge passing through the cross section of a conductor in one second

current density at a point is the current per unit area around that point,area being taken perpendicular to the direction of the current

electric current through a metallic conductor is directly proportional to the potential difference across is provided temperature and other physical conditions are a constant

electric resistance is the opposition offered by a conductor to the flow of electrons