JEE Main · 2021 · 27 Aug 2021 · Shift 1 · Units & Measurement

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Which of the following is not a dimensionless quantity?
  1. (A)Relative magnetic permeability ( )
  2. (B)Power factor
  3. (C)Quality factor
  4. (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

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