Question

Give the dimensional formula for magnetic permeability of free space.

(a) [M L T^-2 A^-2]

(b) [M^2 L T^-2 A^-2]

(c) [M L^2 T^-2 A^-2]

(d) [M^-1 L T^-2 A^-2]

The question was posed to me during a job interview.

This intriguing question comes from Magnetic Field due to a Current Element & Biot-Savart Law in chapter Moving Charges and Magnetism of Physics – Class 12

Answer 1

Right answer is (a) [M L T^-2 A^-2]

The explanation: Magnetic permeability = Magnetic flux density × [Magnetic field strength]^-1.

μ = [M L^0 T^-2 A^-1] × [M^0 L^-1 T^0 A^1]^-1

μ = [M L T^-2 A^-2].