SI base unit SI base unit The International System of Units (SI) defines seven units of measure as a basic set from which all other SI units can be derived. The SI base units and their physical quantities are the meter for measurement of length, the kilogram for mass, the second for time, the ampere for electric current, the kelvin for temperature, the candela for luminous intensity, and the mole for amount of substance. The SI base units form a set of mutually independent dimensions as required by dimensional analysis commonly employed in science and technology. The names and symbols of SI base
Electric current wire he deduced that the heat produced was proportional to the square of the current multiplied by the electrical resistance of the wire. This relationship is known as Joule's First Law. The SI unit of energy was subsequently named the joule and given the symbol "J". The commonly known unit of power, the watt, is equivalent to one joule per second. In an electromagnet a coil, of a large number of circular turns of insulated wire, wrapped on a cylindrical core, behaves like a magnet when an electric current flows through it. When the current is switched off, the coil