Question

A long vertical wire carrying a current of 10A in the upward direction is placed in a region where a horizontal magnetic field of magnitude 2.0 * 10^-3 T exists from south to north. Find the point where the resultant magnetic field is zero.

Answer 1

[IMG]

Here x is the distance of point P from the wire which is unknown.

Hence plug the value of given data to B formula:

$B = \mu \times I/2 \times 3.14 \times (x)$

$\mu$ is constant $(4 \times 3.14 \times 10 ^{-7})$

2 \times 10^-3 = 4 \times 3.14 \times 10^-7 \times \frac {10}{2} \times 3.14 times (x)

Hence $x = \frac {2 \times 10^{-6}} {2 x 10^{-3}} \\= 10^{-3} m$