Question

If number of turns per unit length of a coil of a solenoid is doubled, its self-inductance will

• A. Remain constant
• B. Be doubled
• C. Be halved
• D. Be four times

Answer 1

The correct option is D

Be four times

$\text{L}={\mu }_0{n}^2\text{A}l$ i.e., $\mu \propto n^2$

When n is doubled, L becomes four times its initial value.