Which of the following is not a dimensionless quantity?
- (A)Relative magnetic permeability ( )
- (B)Power factor
- (C)Quality factor
- (D)Permeability of free space ✓ Correct
Answer: (D)
Solution
Relative permeability is a ratio of two permeabilities, the power factor is a ratio of powers, and the quality factor is a ratio of energies, so all three are pure numbers. The permeability of free space, , has dimensions (unit ), so it is not dimensionless.
JEE Main · 2021 · 27 Aug 2021 · Shift 1 · Single correct option