Question

A long solenoid has 200 turns per $cm$ and carries a current of $2.5 A.$ The magnetic field at the center is $\left(\mu_{0}=4 \pi \times 10^{-7} Wb / m - A \right)$

• A. $5.41 \times 10^{-3} Wb / m ^{2}$
• B. $6.28 \times 10^{-2} Wb / m ^{2}$
• C. $2.2 \times 10^{-4} Wb / m ^{2}$
• D. None of these

Answer 1

Answer: (B)

$B =\mu_{ o } nI =4 \pi \times 10^{-7} \times \frac{200}{10^{-2}} \times 2.5$
$B =6.28 \times 10^{-2} Wb / m ^{2}$