Problems IV

Question $1.$ Answer the following questions.

As shown in Figure $1($a$),$ a steady$-$state current of magnitude I flows through the straight conductor. Show that the magnetic field at point $($P$)$ at distance $R$ from the conductor is

$H_{AB}=\frac{\text{I}}{4R}(cos{}_1-cos{}_2)$

As shown in Figure$1($b$),$ a steady$-$state current of magnitude I flows through in a square conductor circuit ABCD with on side length $a$ in the $x-y$ plane. Using result $($a$),$ find the magnetic field at the point P at distance $Z$ on the central axis.

$($b$)$

Figure $1.$ Figures for Question $1$