Category: Physical Quantities, Units and Measurements

Physical Quantity	SI Unit	Symbol
Length	metre	m
Mass	kilogram	kg
Temperature	Kelvin	K
Time	second	s
Current	ampere	A
Amount of substance	mole	mol
Luminous intensity	candela	cd

It is a physical quantity with only numerical magnitude.

Examples: mass, energy, time, volume, density, power, temperature, speed.

It is a physical quantity with both numerical magnitude and direction.

Examples: force, velocity, acceleration, weight, displacement.

A physical quantity is a quantity that can be measured.

It consists of a numerical magnitude and a measurement unit.

Eg, length, area, volume, velocity, acceleration

Diameter of an atom: 10^-10 m

Diameter of Earth: 1.2742 x 10⁷ m

Thickness of a strand of human hair: range from 17 x 10^-6 m to 181 x 10^-6 m

Length of a bus: 14 m

Diameter of a pin head: 1.5 x 10^-3 m