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

Answer: (C)

may have a unit

A dimensionless quantity may have a unit but cannot be expressed in terms of seven fundamental SI quantities. For example, angle is a dimensionless quantity with unit radian but radian cannot be expressed in fundamntal SI quantities.