## In This post you will get answer of Q.

In figure two parallel infinitely long current carrying wires are shown. If resultant magnetic field at point $A$ is zero. Then determine current $I$.

Solution:

## at A$quad$$quad$ B_{1} + B_{2} = 0

$frac{mu_{0}i_{1}}{2pi r_{1}}=frac{mu_{0i_2}}{2pi r_{2}}$

$frac{i_{1}}{27}=frac{10}{9}$

$I=30A$