Question

A dimensionless quantity :

• A. may have a unit
• B. never has a unit
• C. always has a unit
• D. does not exist

Answer 1

The correct option is A may have a unit

A quantity is not always meant to have the basic physical units as its unit like the length, mass, time, temperature, etc. There are several quantities that do not have any physical unit but are widely used in measurements.

For ex: The units like radians, strain, etc. They are dimensionless but represent a quantity and are used in the measurement.

Option $A$ is correct.