Question

Which of the following physical quantities has no units?

• A. relative density
• B. density
• C. pressure
• D. thrust

Answer 1

Answer: (A)

relative density

Density has SI unit as $kg/m^3$

Pressure has SI unit as $P$(Pascal)

Pressure has SI unit as $N$(Newton)

Relative Density$=\frac{\text{Density of one substance}}{\text{Density of another substance}}$

Hence relative density has no unit.