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JEE Main202127 Aug 2021Morning ShiftPhysicsUnits and DimensionsActual

Which of the following is not a dimensionless quantity?

Options

  1. APower factor
  2. BQuality factor
  3. CPermeability of free space μ 0
  4. DRelative magnetic permeability μ r

Correct answer

C. Permeability of free space μ 0

Step-by-step solution

The power factor is defined as, cos ϕ which is dimensionless, the formula of quality factor, Q = 1 R L C , which is also dimensionless, and the permeability in free space, μ r = μ μ 0 , but permeability in free space is defined as, μ 0 = c 2 ε 0 , here c is the speed of light in vacuum and ε 0 is the permittivity in free space so this having dimension.

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