All the derived physical quantity can be expressed in the terms of some combination of the seven fundamental or base quantities. We call these fundamental quantities as the seven dimensions of the world, which are denoted with square or big brackets [ ].
These 7 Dimensions are as under-
Dimension of Length = [L]
Dimension of Mass = [M]
Dimension of Time = [T]
Dimension of Electric Current = [A]
Dimension of Thermodynamic Temperature = [K]
Dimension of Luminous Intensity = [cd]
Dimension of Amount Of Substance = [mol]
The expression which shows how and which of the fundamental quantities represent the dimensions of a physical quantities is called the dimensional formula of the given physical quantity.
Example:- The dimensional formula of volume is [M⁰L³T⁰]
The equation obtained by equating a physical quantity with its dimensional formula is called the Dimensional Equation of the given physical quantity.