# Deducing Relation among the Physical Quantities

The method of dimensions can sometimes be used to deduce relation among the physical quantities.

For this we should know the dependence of the physical quantity on other quantities (up to three physical quantities or linearly independent variables) and consider it as a product type of the dependence.

Dimensional analysis is very useful in deducing relations among the interdependent physical quantities.

However, dimensionless constants cannot be obtained by this method. The method of dimensions can only test the dimensional validity, but not the exact relationship between physical quantities in any equation.

It does not distinguish between the physical quantities having same dimensions.