hey, i was just confused here, which is the right formula for finding the self inductance of a solenoid, given the number of turns, the cross-sectional area, the length, and the current. is it L = Uo x Ur x N^2 x A / L (Uo = mu o, Ur = mu r)?? pls if it is wrong, let me know the right formula. thanks! Monsurat.