About Ṁeasurement

Measurement

Ṭhe  Comparision of an unknown quantity with the known standard quantity is called measurement. The branch which deals with the study of measurement is called metrology. 

Importance of measurement

1.  Measurement is important to cook food.
2.  It is important to buy and sell goods.
3.  It is important to construct roads, bridges, etc.
4. Measurement is important to sew clothes.
5. Measurement is important to perform scientific research in their calculation.

Physical quantity 

Those quantities which can be measured are called physical quantities. There are two types of physical quantities. They are:

• Fundamental physical quantity.
• Derived physical quantity.

Fundamental physical quantity

Those physical quantities which do not depend on other quantities are called fundamental quantities. There are only seven fundamental quantities. They are given below:

No.	Fundamental Physical Quantities
1.	Length
2.	Mass
3.	Time
4.	Temperature
5.	Electricity
6.	Luminous intensity
7.	Quantity of matter

Length

Length is the shortest distance between any two points. The S.I unit length is Meter (M). It can be measured by using measuring tape.

Mass

The total amount of matter contained in a body is called mass. The S.I system of measurement is Kilogram. Mass can be measured by using beam balance. Mass is not affected by gravity.

Time

The duration or intervals between any two events is called time. Its SI units are second. Time can be measured by using different watches.

Derived Physical quantity

Those quantities which depend on other quantity are called derived physical quantities. They are more in number. Some of the examples of derived physical quantities are area, volume, density, perimeter, power, etc.

Weight

Weight is the force of gravity exerted in a body. Its S.I unit is Newton. It can be measured by using a spring balance. It is affected by gravity.

System of measurement

The most commonly used system of measurement is given below.

• M.K.S system of measurement
• F.P.S system of measurement
• C.G.S system of measurement

M.K.S system of measurement

The system of measurement in which length is measured in meter, mass is in kilogram, and time is in second is called the M.K.S  system of measurement. It is also called the metric system of measurement. 

F.P.S System of measurement

The system of measurement in which length is measured in the foot, mass is in the pound, and time is in second is called the F.P.S system of measurement. It is also called the British system of measurement.

C.G.S system of measurement

The system of measurement in which length is measured in centimeter, mass is in gram, and time is in second is called C.G.S system of measurement. It is also called the french system of measurement.

S.I system of measurement

The extended version of the M.K.S system of measurement and which is accepted by all over the world is called the S.I system of measurement.

Unit

The standard reference which is used to measure physical quantities is called unit. There are two types of units. They are given below

• Fundamental unit
• Derived unit

Fundamental unit

Those units which do not depend on other units are called fundamental units. There are altogether seven fundamental units. They are given below with their fundamental physical quantities.

No.	Fundamental Physical Quantities	Unit
1.	Length	Meter(M)
2.	Mass	Kilogram (Kg)
3.	Time	Second (S)
4.	Temperature	Kelvin (K)
5.	Electricity	Ampere (A)
6.	Luminous intensity	Candela (Cd)
7.	Quantity of matter	Mole (mol)

Derived units

Those units which depend on other units are called derived units. Derived units are more in number. Some of the examples of derived units are listed below with their derived physical quantities.

No.	Derived Physical Quantities	Unit
1.	Area	Square Meter
2.	Volume	Cubic Meter
3.	Density	Kilogram per cubic meter
4.	Force	Newton
5.	Work and energy	Joule
6.	Power	Watt
7.	Pressure	Pascal

Difference Between

• Fundamental physical quantities and Derived physical quantities

No.	Fundamental Physical Quantities	Derived Physical quantities
1.	Those physical quantities which do not depend on other quantities are called fundamental physical quantities.	Those physical quantities which depend on other quantities are called derived physical quantities.
2.	There are altogether seven fundamental physical quantities.	Derived physical quantities are more in numbers.
3.	The unit of fundamental physical quantities is also called a fundamental unit.	The unit of derived physical quantities is also known as a derived unit.
4.	Example: Mass, length, electricity, etc	Examples: force, speed, power, work, etc

• Fundamental unit and Derived unit

No.	Fundamental Unit	Derived Unit
1.	Those units which do not depend on other units are called fundamental units.	Those units which depend on other units are called derived units.
2.	There are altogether seven fundamental units	Derived units are more in numbers.
3.	Example: Kilogram, meter, second, ampere, etc.	Examples: square meter, cubic meter, kilograms per cubic meter, etc.

• Mass and weight

No.	Mass	Weight
1.	The total amount of matter contained in a body is called mass.	The force of gravity exerted in a body is called weight.
2.	The S.I unit of mass is Kilogram.	The S.I unit of weight is Newton.
3.	It is a fundamental physical quantity.	It is a derived physical quantity
4.	It is not affected by gravity.	It is affected by gravity.
5.	It can be measured by using beam balance.	It can be measured by using a spring balance.