# Physics – Fundamental Quantities and Units

Fundamental units: The parts of a physical amount that cannot be obtained from each other are called the basic units. For example, in mechanics, meters, kilograms and seconds are the basic units for length, mass and time.

Derived units: The units of other end quantities derived from the base units are called derivative units, such as derivative units like Newton, Pascal, Joule, and Volt, respectively, for force, pressure, function and potential.
Major counting methods are low
c.GS. (CWS) method- In this method, length, mass and time units are centimeters, grams, seconds respectively. It is also called French or Metric method.
M.K.s. (Mc) method – In this method the units of length, mass and time are meter, kilogram, second respectively.
E.P.S. (F.P.) Method- In this method, the units of length, mass and time are feet, feet, seconds respectively, it is also called British method.
S.I. (International system) method – M.K.S. The method is modern, this is called international method. 5.). The method consists of seven basic units and two complementary units.

## Basic unit

(1) Length-meter
(2) mass-kilogram
(3) second of time
(4) electric current-ampere
(5) heat-kelvin
(6) Jyoti intensity Candela
(7) Acquire volume of substance

#### Supplementary units are radian and steradian.

Distance units –
1 Parsec-3086×10 ° m -3.26 light years
1 light year-945×104 km-946×1015 m
1 Agstrom – 10-10 Motor, 1 Micron – 10mm-10m
1 Nautical Mile – 1.852 km

#### Volume units:

1 liter-02642 gallon 1 gallon – 3.785 liters
Light year: A light year is the distance traveled in a year by light in a vacuum. It is the unit of distance of celestial bodies.
• Parsec; It is the largest unit for measuring distance of celestial bodies. Parsec – 3.26 light years
• Astromornical Unit: This is equal to the average distance of the Earth from the Sun (14.96 million km).