Eight wires cut the page perpendicular to the points shown. Each wire carries current `i_(0)`. Odd currents are out of the page and even current into the page. Find the line integral `ointvec(B).vec(dl)` along the loop.

Explanation

According to Ampere's, circuital law
`ointvec(B.)vec(dl.)=mu_(0)i_(enclosed),ointvec(B).vec(dl)=mu_(0)[i_(g)-i_(5)+i_(2)+i_(4)]`

Since, all the wires carry same current of `i_(0)`, we have `ointvec(B).vec(dl)=2mu_(0)i_(0)`.