Infinite wires, each carrying a current 0.5 A, are kept parallel to y-axis and intersecting x-axis at `x=+-1` m, `+02 m`, `+-4 m`, `+-8m` etc. Wires kept at positive values of x carry current in the same direction while wires kept at negative values of x carry current successively in opposite directions as shown in Fig.

A wire is kept parallel to x-axis and intersecting y-axis at y=2 m. It carries a current i. Assuming this wire to be insulated from others then the current i in it such that magnetic induction at O is zero is
(assuming each wire to be infinitely long)