Practice portal › Moving Charges and Magnetism › Biot-Savart Law: Straight Wires and Arcs
Asked in GUJCET 2024 · Units and dimensions
Given: the unit (V s)/(A m).
Idea: group it as (V s)/A divided by a metre.
Now V s=Wb, so (V s)/A=(Wb)/A=H, the henry -- this is just L=Φ/I read as a unit.
The whole unit is therefore H m⁻¹, an inductance per unit length.
That is exactly how μ₀=4π×10⁻⁷ H m⁻¹ is quoted, and L=μ₀n²ℓ A shows why: μ₀ is what fixes the inductance of a given piece of geometry.
So (V s)/(A m) is the unit of μ₀, the permeability of free space.
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