## International System (SI) of Units

The International System of Units (abbreviated SI from systeme internationale , the French version of the name) is a scientific method of expressing the magnitudes or quantities of important natural phenomena. There are seven base units in the system, from which other units are derived. This system was formerly called the meter-kilogram-second (MKS) system.

All SI units can be expressed in terms of standard multiple or fractional quantities, as well as directly. Multiple and fractional SI units are defined by prefix multipliers according to powers of 10 ranging from 10^{-24} to 10^{24}.

The SI-unit system is just a convention in which the MKS unit system is adopted universally. In practice, also the CGS (centimete/gram/second) system is also used.

Unit------- Symbol--Dimension