Write down different system of unit . explain S.I. system of units.

Write down different system of unit . explain S.I. system of units

Answer :- A measuring system is based on few fundamental units 

                e.g. Lenght, Mass, Time , Temperature etc . All the physical

                quantities is being expressed in terms of these fundamental units . 

(a)  F. P. S. System :-  Here, the lenght is measured in yard, mass, weight or force in pound, time in seconds and temperature is degree forenheit.

(b)  Metric system :- Here, the lenght is measured in meter mass in kilogram force in kilogram force, time in second and temperature  in degree centigrade .

(c)  S.I. System :- this system is extension and refinement of the meter system . Here, the lenght is expressed in meter, mass in kg, force in newton, time in second etc. It is based on decimal arithmetic.

(d)  C.G.S System :- In this system, the unit of lenght of lenght, mass and time are centimeter, gram and second.

(e)  M.K.S System :- In this system, the unit of lenght, mass and time are meter, Kilogram and Second. 

This system is extension and refinement of the meter system. .

Here, the lenght is expressed in metre, mass in kg, force in newton, 

time in second etc. It is based on decimal arithmetic.  

S. No.   physical quantity             Unit         Symbol

1. Lenght                                    Meter             M
2. Mass                                      Kilogram      Kg 
3. Time                                       Second        S
4. Temperature                           Kelvin          K 
5. electric current                        Ampere       A
6. luminous intensity                   Candela      Cd  
7. Quantity of substance             Mole            Mole