Question

A solenoid of 2500 turns wound uniformly over a length of 0.5 m on a cylindrical paper tube, 4cm in diameter. The inductance of the solenoid is ________mH (Assume air medium )

• A. 19.7

Answer 1

The correct option is A 19.7
Inductance is obtained by,

$L={\mu }_0\frac{N^{2}A}{l}$

Where, A = $\pi r^2=\pi \times (2\times {10}^{-2}{)}^2$

$L=\frac{4\pi \times {10}^{-7}\times (2500{)}^2\times \pi \times (2\times {10}^{-2}{)}^2}{0.5}$

Inductance, L = 19.7 mH