Physics Class 9th
Chapter no 01
Question no 03
What is SI ?Name SI base quantities and their units.
Answer
Unit: The standard with which the the standard with which the other things are compared is called a unit.
History of SI: The scientists prefer this system( SI unit) for the exchange of their scientific researches and information with worldwide scientific community.The 11th general conference on weight and measures held in Paris in 1960 adopted a new world wide system of measurements called International System of units (SIU).
Definition of SI: A complete set of units for all physical quantities is called system of unit (SI). This is abbreviated SI.
SI Base Quantities: The following are the seven Si base physical quantities and their units.
Define base units and derive units?
SI base units: The units of base physical quantities are called base units.
There are 7 base units.. given in the table above .Derived units: The units of derived physical quantities are called derived units.
Examples. Area = m*2F
Force= N = kgm*
