Question

Two coaxial solenoids are made by winding thin insulated wire over a pipe of cross-sectional area $A=10\, cm ^{2}$ and length $=20\, cm$. If one of the solenoid has $300$ turns and the other $400$ turns, their mutual inductance is $\left(\mu_{0}=4 \pi \times^{-7} Tm A^{-1}\right)$

• A. $2.4 \pi \times10^{-5} H$
• B. $4.8 \pi \times10^{-4} H$
• C. $4.8 \pi \times10^{-5} H$
• D. $2.4 \pi \times10^{-4} H$

Answer 1

Answer: (D)

$M =\frac{\mu_{0} N _{1} N _{2} A }{1}$
$=\frac{4 \pi \times 10^{-7} \times 300 \times 400 \times 10 \times 10^{-4}}{0.2}$
$=2.4 \pi \times 10^{-4} H$