Problem 12.3

a) Consider a wire of length 2L along the z axis, where a current I flow from z = ?L to z = L as shown in the figure. Determine the vector magnetic potential about a point on the y-axis at a distance R from the origin. Derive the value of the magnetic potential in the limit L?R.

b)A new wire of length 2L is placed, parallel to the wire of the previous part, through which a current Icirculate in the opposite direction. The new wire is located at a distance d from the first, perpendicular to the xy plane (see figure). Determine the vector magnetic potential for points on the xy plane at distances much greater than L.