Units for Measurement
The chosen standard of measurement of a quantity which has essentially the same nature as that of the quantity is called the unit of the quantity. Following are the important types of system for unit,
(1) C.G.S. System: Length (centimetre), Mass (gram), Time (second)
(2) M.K.S. System: Length (metre), Mass (kilogram), Time (second)
(3) F.P.S. System: Length (foot), Mass (pound), Time (second)
(4) S.I. System: The 11th general conference of weights and measures (October 1960) adopted International system of units, popularly known as the SI units. The SI has seven basic units from which all other units are derived called derived units. The standard prefixes which helps to reduce the basic units are now widely used.
Amount of substance
Table: Seven basic S.I. units