Question

When the number of turn in a coil is doubled without, any change in the length of the coil , its self inductance becomes

Answer 1

We know that,

Self-inductance of a solenoid $=\frac{\mu A{n}^2}{l}$

So, self-induction proportional to $n^2$

So, induction becomes $4$ times when $n$ is doubled.

Hence, this is the required solution