Question

The coaxial solenoids are made by winding thin insulated wire over a pipe of cross-sectional area $A=10c{m}^2$ and $length=20cm$. If one of the solenoid has $300$ turns and the other $400$ turns, their mutual inductance is
$({\mu }_0=4\pi \times {10}^{-7}Tm{A}^{-1})$

• A. $2.4\pi \times {10}^{-5}H$
• B. $4.8\pi \times {10}^{-4}H$
• C. $4.8\pi \times {10}^{-5}H$
• D. $2.4\pi \times {10}^{-4}H$

Answer 1

The correct option is D $2.4\pi \times {10}^{-4}H$

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

$=\frac{4\pi \times {10}^{-7}\times 300\times 400\times 100\times {10}^{-4}}{0.2}$

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