If both the number of turns and length of an inductor are tripled, keeping other factors constant, the self-inductance of the inductor will be
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → tripled
The self-inductance of a long solenoid of \( N \) turns, length \( l \) and cross-section \( A \) is
\( \displaystyle L = \frac{\mu_{0}N^{2}A}{l} \)
So \( L \propto N^{2}/l \) when the other factors stay the same.
\( \displaystyle \frac{L'}{L} = \frac{(3N)^{2}/(3l)}{N^{2}/l} = \frac{9}{3} = 3 \)
The self-inductance is tripled.