Physical Quantity And System Of Units

"Any quantity that are measured in physics are called as physical quantity."

➡Physical quantity measurement required a magnitude and an unit.

➡Physical quantity measurement= magnitude (N) X unit (U)

➡Here Magnitude tells about number of times the unit is present in physical quantity 

and  Unit tells about a standard that is used to measure a physical quantity.

 

Types of physical quantity:

1. Fundamental quantity

2. Derived quantity

1. Fundamental quantity

➡Physical quantity which is independent of any other quantities is called as  

fundamental quantity.

➡Fundamental quantity is also called as Basic quantity

Example: Length, mass, time

2. Derived quantity

➡A physical quantity which can be obtained from fundamental quantity is called a  

derived quantity.

Example: Area, speed, etc

System of units:

➡To measure Physical quantities 3 Types of System of units are being used,

1. F.P.S system

➡Unit of length is foot

➡Unit of mass is pound

➡Unit of time is second

2. C.G.S system

➡Unit of length is centimetre

➡Unit of mass is gram

➡Unit of time is second

3. M.K.S/ S.I system

➡Unit of length is metre

➡Unit of mass is kilogram

➡Unit of time is second