PHYSICAL QUANTITIES | BASE QUANTITIES & DERIVED QUANTITIES | SI UNITS | BASE UNITS AND DERIVED UNITS

PHYSICAL QUANTITIES BASE QUANTITIES & DERIVED QUANTITIES INTERNATIONAL SYSTEM OF UNITS BASE UNITS & DERIVED UNITS EXPLAINED BRIEFLY IN URDU/HINDI CHAPTER 1 9TH CLASS PHYSICS

• Physical Quantities:

All measurable quantities are called physical quantities like length, mass, temperature and time.

Two common things we see while measuring any physical quantity; its numeric value and unit.

Just for instance, when we have to buy 2 dozens of eggs, we require the shopkeeper to give 2 dozen of eggs. We don’t say him to give us only ‘2’ or only ‘dozen’. Therefore, every physical quantity will be incomplete to describe until we describe its numeric value and its unit as well.

There are two types of physical quantities.

• Base Quantities:

Base quantities are those from which other physical quantities can be derived. There are seven base quantities from which all other physical quantities are derived. These are length, mass, time, electric current, temperature, intensity of light and number of moles.

• Derived Quantities:

Derived quantities are those which are derived from the base quantities. Area, force, work, energy, volume and acceleration etc. are derived quantities.

• International System of Units:

In 1960, in a general conference in Paris on weights are measurements, a universal system of units was made which is called International System of units.

This is because when we set some standard units, we don’t face any difficulty in measuring all physical quantities even we are here or at any place of the World. This is why International System of units was the best idea to overcome this problem.

There are two types of units.

• Base Units:

Units used to describe the base quantities are called base units.

Quantity	Unit	Quantity	Unit
Length (l)	Meter (m)	Mass (m)	Kilogram (kg)
Time (t)	Second (s)	Intensity of light (L)	Candela (cd)
Temperature (T)	Kelvin (K)	Electric current (I)	Ampere (A)
No. of moles (n)	mol

• Derived Units:

Units used to describe the derived quantities are called derived units.

Quantity	Unit	Quantity	Unit
Area (a)	Meter square (m2)	Volume (V)	Cubic meter (m3)
Velocity (v)	Meter per second (ms-1)	Force (F)	Newton (N)/kgms-2
Electric charge (Q)	Coulomb (C)/As	Work (W)	Joule (J)/Nm

For understanding more comprehensively, watch the video from start to end and get to know about physical quantities, base quantities, derived quantities, SI units, base units and derived units in an easy way.

Here is the video lecture explaining; what are physical quantities? Which factors are necessary to describe a physical quantity? How many types of physical quantities are there? What are base quantities? What are derived quantities? What is International System of units? What are base units? What are derived units? How derived quantities are derived from the base quantities? How derived units are derived from the base units? If there's still any confusion regarding this video lecture, you can comment or contact us directly through social links provided so your comments will e entertained gladly. Get everything related to study and academic content through this blog and YouTube channel for useful and important notes and materials.

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