Self inductance of an air coredsolenoid \((L=130mH)\) depends on

1. the total no. ofturns (N) of the solenoid

2. the length \((l=30 cm)\) of the soldnoid

3. the area of thecross section \(\displaystyle{\left({A}=\pi{\left({2.6}\right)}^{{{2}}}\right)}\) of the solenoid

\(\displaystyle{L}=\mu_{{{0}}}{\frac{{{N}^{{{2}}}}}{{{l}}}}{A}\)

substituting the values we can find N

on solving, we get \(N = 38\) turns