1. Tardigrade
  2. Question
  3. Physics
  4. Which of the following physical quantities has neither dimensions nor unit?

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. Which of the following physical quantities has neither dimensions nor unit?

NTA AbhyasNTA Abhyas 2022

Solution:

Unit less physical quantities are always dimensionless. For example, refractive index and relative density. These quantities are the ratio of same physical quantities.
A dimensionless physical quantity may have a unit. For example, plane angle and solid angle. The unit of plane angle is radian but it is dimensionless.
Now,
$\text{Coefficient of friction}=\frac{\text{friction force}}{\text{Normal reactiom}}$
$=\frac{\left[\text{MLT}^{- 2}\right]}{\left[\text{MLT}^{- 2}\right]}$ = no dimensions
Unit= $\frac{\text{N}}{\text{N}}$ = no unit
The coefficient of friction is the ratio of two forces. Hence, it is dimensionless. It also don't have any unit.