How to derive it
Start from a formula that defines resistivity, then replace each quantity with its dimensions. M is mass, L is length, T is time, A is electric current.
- Rearrange: ρ = R A ÷ l
- = [ML²T⁻³A⁻²] × [L²] ÷ [L]
- So [resistivity] = [ML³T⁻³A⁻²], also written [M¹L³T⁻³A⁻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 resistivity?
[ML³T⁻³A⁻²] (or [M¹L³T⁻³A⁻²]), from R = ρl ÷ A. Its SI unit is Ω m.
What are the dimensions of resistivity?
M: 1, L: 3, T: -3, A: -2.
What is the SI unit of resistivity?
Ω m.