Dimensional analysis in Physics is a very essential tool.
There are two types of physical quantities -- Fundamental Quantities ( Primary) & Derived Quantities ( Secondary).
Those quantities which are independent completely are called Fundamental Quantities and there are seven fundamental quantities in our universe we have made for easy learning physics -- Mass, length, Time, Current, Intensity of Light, amount of substance & temperature.
There are special symbols for representing these fundamental quantities --
[M] for mass
[L] for length
[T] for time
[A] for current
[Cd] for Candela, unit of intensity of light
[Mol] for amount of substance
To study dimensional analysis we take mass, length and time as fundamental quantities of every other derived physical quantity.
Derived Quantities in physics are those quantities which depend on fundamental quantities. For example velocity is a derived quantity because --
Velocity = distance / time, it involves fundamental quantities like distance (length) and time.
We have a method in physics writing these physical quantities in the form of M, L & T. And the power raised (exponent) to these fundamental quantities are called Dimensions.
Solving Dimensional Analysis Problems - Unit Conversion Problems Made Easy!__________________
JEE - Study Guide - 1. Some basic concepts of chemistry