Q. A wire of fixed length is wound in such a way that it forms a solenoid of length ' $l$ ' and radius ' $r$ '. Its self-inductance is found to be $L$. Now if same wire is wound in such a way that it forms a solenoid of length $l / 2$ and radius $r / 2$, then the self-inductance will be
Electromagnetic Induction
Solution: