Question

A dimensionless quantity ______.

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

Answer 1

The correct option is C

may have a unit

A dimensionless quantity need not always have a unit, example: angular displacement, θ is dimensionless but has a unit of radians, and quantities like co-efficient of friction, have no dimensions and no units.