3) UNITS & MEASUREMENTS

UNIT: Accepted standards for measuring physical quantity are known as Units.


Classification of Units:   a) Fundamental Units.

                                     b) Derived Units.

                                     c) Absolute and Gravitational Units.

a) Fundamental Units: The units of fundamental physical quantities (length, mass ,time) are known as fundamental units.
   Fundamental Units are further sub-divided into M.K.S., C.G.S., & F.P.S. Systems.


                    Out of them MKS & CGS are known as Metric Systems & FPS is known as British System.




Fundamental Physical Quantity Fundamental Unit

Length Metre -m

Mass Kilogram -kg

Time Second -s

e.g.











Fundamental Units are further sub-divided into M.K.S., C.G.S., & F.P.S. Systems.

Out of them MKS & CGS are known as Metric Systems & FPS is known as British System.



Length Mass Time



Metric systems.

M.K.S. System.

m

kg

s



C.G.S.System.

cm

g

s



British Imperial system.

F.P.S. System.

foot

pound

s



Further examples of primary/fundamentals units are : ampere, Kelvin, candela, mole.

Supplementary units: rad (Radian-For measurement of Plane angle).

steradian (Steradian-For measurement of Solid angle ).