Write a note on $SI$ (Systeme Internationale) units.

(N/A) The $SI$ (Systeme Internationale d'Unites) is the internationally accepted system of units.
- It is the modern form of the metric system and is abbreviated as $SI$.
- The $SI$ system consists of $7$ fundamental physical quantities: length,mass,time,electric current,thermodynamic temperature,amount of substance,and luminous intensity.
- These fundamental quantities,along with their units and symbols,were established and recommended by the General Conference on Weights and Measures $(CGPM)$ in $1971$ for international use in scientific,technical,and commercial fields.
- The $SI$ system is based on the decimal system,which makes conversions between units simple and convenient.