Question

A current of $10A$ is flowing through a long and straight brass wire. The magnetic induction at a distance $0.5cm$ from the wire is (in $Wb/m^2$ )

• A. $4\times {10}^{-3}$
• B. $4\times {10}^{-2}$
• C. $4\times {10}^{-4}$
• D. $4\times {10}^{-5}$

Answer 1

Answer: (C)

$4\times {10}^{-4}$

$B=\frac{{\mu }_{0}i}{2\pi r}$
$B=\frac{2\times {10}^{-7}\times 10}{0\cdot 5\times {10}^{-2}}$
$=4\times {10}^{-4}T$