When the number of turns of a solenoid is doubled, its self inductance becomes:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 4 times
The self inductance (L) is,
$L=μ_0\frac{N^2A}{l}$
if the number of turns N is doubled:
$L'=\frac{μ_0(2N)^2A}{l}=4\frac{μ_0N^2A}{l}$
$L'=4L$