All measureable quantities are called physical quantities such as length, mass, time and temperature. A physical quantities possesses at least two characteristics in common. One is its numerical magnitude and other is the unit in which it is measured. For example, if the length of a student ia 104 cm then 104 is its numerical magnitude and centimetre is the unit of measutement.
Physical quantities are divided into two typs.
- Base quantities
- Derived quantities
There are seven physical quantities which are form the foundation for other physical quantities are called base quantities. These are length, mass, time, electric current, temperature, intensity of light and the amount of a aunstance.
Those physical quantities which are expressed in yerms of base quantities are called derived quantities. These include area, volume, charge, electric potential etc.