Inductance per unit length

Inductance per unit length near the center of a solenoid can be expressed as:-

L/e=(μ_0*n^2*A)

Where:-

L = inductance [H]
 l = length of the solenoid [m]
 μ_0 = the permeability of free space 4p×10-7 Tm/A
 n = number of turns of wire per unit length [#/m]
 A = area [m2]