Question

Write a short note on the following.

Dimensionless quantities

Answer 1

There are two types of dimensionless quantities –

(i) dimensionless variable and

(ii) dimensionless constant.

• Dimensionless variables – Physical quantities which have no dimensions but have variable values are called dimensionless variables.
  Examples: specific gravity, strain, refractive index, etc.
• Dimensionless constants – Quantities that have constant values and also have no dimension are called dimensionless constants.
  Example: π, e, numbers, etc.