Q 12-06-020NEETJEE MainMedium
The self-inductance of a solenoid is $L$. If the number of turns is doubled, keeping its length and area the same, the self-inductance becomes
Answer: (B) $4L$
$L = \dfrac{\mu_0N^2A}{l} \propto N^2$, so it becomes $4L$.
Solution by Sreeraj P, M.Sc Physics