In Fig. two long parallel wires (seen end-on) that are a distance R apart carry equal currents i in the same sense. Find the magnitude of the magnetic field at point P , which lies quidistant from the two wires at an angle `theta` from the plane of the wires.

Explanation

`B_("net") =2B cosphi=2xx(mu_0I)/(2pir)cos phi`
Let `r=R/(2cos theta)` and `phi=90- theta`
Then `B_("net")=(mu_0I)/(piR/2)cos thetacos(90- theta)`
`implies vecB_("net")=(2mu_0I)/(piR) cos theta sin theta(hati)` towards right