Question

Dimensionless Quantity.

Answer 1

Dimensionless Quantity : In the equation $[ Y ]=\left[ M ^{a} L ^{b} T ^{c}\right]$, if $a=b=c=0$, then the quantity is called dimensionless.

As for example —

(a) Strain, specific gravity, angle. Thę are ratio of two similar quantities.

(b) Number, such as $9, \frac{1}{4}, \sin \theta, \pi$ etc.

A dimensionless quantity has same numerical value in all system of units.