Ch.1 Units and Measurement (XI science Physics)

                                       Ch.1   Units and Measurement

    Different  system of units based on length, mass and time as fundamental quantity.

        i)  CGS system – centimeter – gram – second system

       ii) MKS system – meter – kilogram – second system

       iii) FPS system – foot – pound – second system

     SI system of unit :Use of different system of units made it very difficult to exchange scientific information between different parts of the world. Hence it has been accepted to use common system of units throughout the world called system international d’ units’ (SI system )in conference held at Paris in 1960.

   It consists of seven fundamental quantities and two derived quantities along with its units. These quantities with units and symbols are as shown in table:

Fundamental quantity	SI unit	symbol
Length	meter	m
Mass	kilogram	kg
Time	second	s
Temperature	Kelvin	k
Electric Current	ampere	A
Luminous Intensity	candela	cd
Amount of substance	mole	mol

  

Supplementary quantity	unit	symbol
Plane angle	radia	rad
Solid angle	steradian	sr