Magnetic Reluctance: Correct Equation

[confusion321]

Which is the correct equation for Magnetic Reluctance ?

R = Reluctance
l = Length
A = Area
\mu = Magnetic Permeability of the material
\mu_0 = Magnetic Permeability of free space (4\pi \times 10^- ^7 tesla/ampere turn)

R = \frac {l} {\mu A} as stated on Wikipedia or R = \frac {l} {\mu_0 \mu A} as stated in my textbook.

 

[Doc Al]

The Wikipedia formula looks correct. Are you sure your book isn't using \mu to mean relative permeability (which is just a ratio)? (If not, the units would make no sense in your book's formula.)

 

[confusion321]

Thanks very much that would be it. "Relative Permeability"