Skin Depth Effect Formula

Equation for calculate skin depth effect is,

$\delta =\sqrt{\raisebox{1ex}{$\rho $}\!\left/ \!\raisebox{-1ex}{$\pi \mu f$}\right.}$

where,
δ is the skin depth
ρ is the frequency
μ is the absolute magnetic permeability (μ) = μ_o x μ_r
m is the permeability of free space 4*π*10⁷ H/m