How can we find the dimensions of any physical quantity in the simplest way????? Please tell me as soon as possible.

The seven fundamental or base quantities chosen in SI units are the seven dimensions. They are denoted within square brackets[ ] .

Length is represented by [L], mass by [M] time by [T] ,electric current by [A] temperature by [K], luminous intensity by [Cd]

and amount of substance by [mol].

The dimensions of a physical quantity are the powers or exponents to which the units of base quantities are raised to represent a derived unit of that quantity.

All physical quantities can be represented in terms of the dimensions of length[L] , mass[M], and time[T]

 

Example: Area = length × breadth = L× L

Dimensional formula = [L]²

Thus to represent area we have to raise [L] to the power 2. Therefore Area is said to have two dimensions in length . As unit of mass and time are not required in representing area , we can write the dimensional formula of area as: [M⁰L²T⁰] and hence we say that area has zero dimension in mass and time in addition to 2 dimensions in length.

Similarly Velocity =displacement / Time

                        =[L] / [T]

Velocity =[LT^-1] =[M⁰L¹T^-1]. This is the dimensional formula of velocity

The dimensions of velocity are : zero in mass. +1 in length and -1 in time.

To find the dimensions :

First the relation of the physical quantity with respect to other quantities have to be known, like density = mass/ volume. And then its written in terms of the dimensions of the fundamental quantities .In such a way you can find the dimensions of any physical quantity.