Question

Derive the expression for the self inductance of a solenoid

Answer 1

let us consider a long solenoid of cross - section area A through which current I is flowing . let L' be the length of thr solenoid ,
φ =NBA = μN²AI/L'
but , φ = LI
LI = μN²AI/L'

L = μN²A/L'

Note :- take μ as miu naught