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
`oint vecB.vecdl = mu_0 i_("enclosed") , oint vecB.vecdl = mu_0 [ i_8- i_s + i_2 + i_4]`

Since , all the wires carry same current of `i_0` , we have `oint vecB.vecdl = 2mu_0 i_0`