They are either dimensionless or can be expressed as a product of one or more of the base units possibly scaled by an appropriate power of exponentiation. The units are divided into two classesbase units and derived units. Table Showing The Seven 7 Fundamental Quantities And Their Si Units Basic Physics Physics Lessons Fundamental The SI unit of electric current is the ampere or amp which is the flow of electric charge across a surface at the rate of one coulomb per second. . First the ampere is defined. If Thus the power consumed in an electrical circuit is said to one watt if one ampere current flows through the circuit when a potential difference of 1 volt is applied across itThe bigger unit of electrical power is the kilowatt kW it is usually used in the power system. Electric fields are usually caused by varying magnetic fields or electric charges. Reference space time mechanics thermal physics waves optics electricit