The Permeability of Free Space, is also called the vacuum permeability or a Magnetic Constant. It is represented using the symbol μ0. The Magnetic Constant can be defined as the the value of magnetic permeability in a classical vacuum. It derived by producing a magnetic field in a vacuum.
The value of Magnetic Constant μ0 can be defined as :
μ0 = 4π×10-7 N/A2 ≈ 1.2566370614...×10-6 H / m or T·m / A or Wb / (A·m) or V·s / (A·m), where Wb for Webers, A for Amps.