Q. Define Physical Quantities and its types.

 Physical Quantity

             A physical quantity is a physical property of a phenomenon, body, or substance that can be quantified by measurement.

A physical quantity can be expressed as the combination of a magnitude expressed by a number usually a real number  and a unit.

Physical quantities are classified into two categories:

1. Fundamental quantities

2. Derived physical quantities

 

1.    Fundamental Quantities

            Physical quantities which cannot be explained by other physical quantities are called fundamental physical quantities.

There are seven fundamental physical quantities and are listed below along with their units.

 

Fundamental Quantitites	S.I Units	Symbol of Unit
Length	meter	m
Mass	kilogram	kg
Time	second	s
Electric Current	ampere	A
Temperature	kelvin	K
Amount of substance	mole	mol
Luminous intensity	candela	cd

 

2.    Derived Quantities

            Physical quantities which are explained on the basis of fundamental physical quantities are called derived physical quantities.For Example

  

Derived Quantitites	S.I Units	Symbol of Unit
Volume	Cubic meter	m3
Velocity	Meter per second	m/s
Force	newton	N
Density	Kilogram per cubic meter	Kg /m3
Acceleration	Meter per second square	m/s2