Question

Explain in detail the derived units - volume, density and temperature. What are derived units?

Answer 1

The units derived from the base or fundamental units are called derived units. These are units of measurement obtained by multiplying or dividing the base units of a system. These units are derived from the seven base units that are specified by the International System of Units.

Complete step by step answer:
First of all let’s discuss fundamental and derived units. A unit of measurement is a definite magnitude of quantity defined and adopted by convention or by law. There are mainly two types of quantities or units i.e. Fundamental and derived quantities. Fundamental units are the units of fundamental quantities. These are the units from which units for derived quantities can be obtained. There are seven fundamental units as given by the International System of units. These are:- Kilogram [unit of weight], meter [unit of length], Second [unit of time], Ampere [unit of current], Kelvin [unit of temperature], mole [unit of mole], Candela [unit of luminous intensity].
A derive unit is a SI unit of measurements derived by combining the required fundamental units. Hence all the units other than fundamental units are called derived units.
Derived Unit of Volume:-
Volume is the amount of space that an object or substance occupies measured in cubic units. The SI unit is cubic meter $\left( {{m^3}} \right)$. $1{m^3}$ signifies the volume of a cube having an edge length of $1m$.
Derived unit of Density:-
Density is defined as the mass per unit volume.
Mathematically it is defined as:-
Density$= \dfrac{{Mass}}{{Volume}}$
The units of density are defined by fundamental units of mass and length. Thus the SI unit of density is Kilogram per cubic meter $\left( {Kg/{m^3}} \right)$.
Derived unit of Temperature:-
The measure of hotness or coldness of a body is known as temperature. As we have already discussed above that temperature is a base/fundamental quantity and it does not have any derived units. SI unit of temperature is Kelvin $\left( K \right)$.

Note:
Some other units like litre, tone, bar and electron volt are neither the SI units of fundamental quantities nor of derived quantities but are widely used in conjunction with SI units. The derived units can either be dimensionless or these can be expressed as a product of one or more of the base units scaled with appropriate power of exponentiation.