How to derive it
Start from a formula that defines permeability of free space μ₀, then replace each quantity with its dimensions. M is mass, L is length, T is time, A is electric current.
- Rearrange: μ₀ = 2πr B ÷ I
- = [L] × [MT⁻²A⁻¹] ÷ [A]
- So [permeability of free space μ₀] = [MLT⁻²A⁻²], also written [M¹L¹T⁻²A⁻²].
Dimensional formulas of other quantities
The full searchable list, with SI units, is on the dimensional formula page.
Questions students ask
What is the dimensional formula of permeability of free space μ₀?
[MLT⁻²A⁻²] (or [M¹L¹T⁻²A⁻²]), from B = μ₀I ÷ (2πr). Its SI unit is T m A⁻¹ (H m⁻¹).
What are the dimensions of permeability of free space μ₀?
M: 1, L: 1, T: -2, A: -2.
What is the SI unit of permeability of free space μ₀?
T m A⁻¹ (H m⁻¹).