[LT⁻¹Q⁻¹]
[LTQ⁻¹]
[ML²T⁻¹Q⁻²]
[MLQ⁻²]
Magnetic permeability of free space = 4π × 10⁻⁷ N A⁻²
The dimension of force is [MLT⁻²]
The dimension of current is [T⁻¹Q]
Hence, the dimension of magnetic permeability of free space is = N/A² = [MLT⁻²][T⁻¹Q]⁻² = [MLT⁻²][T²Q⁻²] = [MLQ⁻²]