CBSE Class 11-science Answered

Dimensional analysis is a method for finding or checking relations among physical quantities by using their dimensions. The dimension of a physical quantity is the combination of the basic physical dimensions (such as mass, length, time, electric charge and temperature) which describes it. Dimensional analysis is based on the fact that a physical law must be independent of the units used to measure the physical variables. For example, the dimension of speed is length per time, LT^-1.

Dimensional analysis has many limitations:

(1) Dimensional analysis provides no information about dimensionless constants.

(2) Dimensional analysis fails in the case of exponential or trigonometric functions.

(3) It fails if the physical quantity depends on more than three other physical quantities.