Question

Two coaxial solenoids are made by winding thin insulated wire over a pipe of cross-sectional area
A = 10cm${}^2$ and length = 20 cm. If one of the solenoids has 300 turns and the other 400 turns, their mutual inductance is

• A. 2.4π× 10⁻⁵ H
• B. 4.8π× 10⁻⁴ H
• C. 4.8π× 10⁻⁵ H
• D. 2.4π× 10⁻⁴ H

Answer 1

The correct option is D

2.4π× 10⁻⁴ H

$m=\frac{{\mu }_0{N}_1{N}_{2}A}{l}$

substituting, $M=2.4\pi \times {10}^{-4}H$