Two infinitely long straight parallel wires carry equal currents ‘i’ in the same direction and are 2 m apart. Magnetic induction at a point which is at same normal distance $\sqrt{2} \mathrm{m}$ from each wire has magnitude 

In three dimensional space, the point lies perpendicular to the plane containing wires. 

Let $\theta$ be the half-angle made by position vector of particle with vertical. Then

$\sin \theta =\frac{1}{\sqrt{2}}\Rightarrow \theta =45°$

If field due to each wire is B

$$\begin{gathered} B_{\text{net }}=2B\cos \theta \\ {B}_{\text{net }}=2\left(\frac{{\mu }_{0}i}{2\pi \sqrt{2}}\right)\frac{1}{\sqrt{2}}=\frac{{\mu }_{0}i}{2\pi } \end{gathered}$$