A thin current element extending between z = —L/2 and z = L/2 carries a current I along +...

A thin current element extending between z = —L/2 and z = L/2 carries a current I along + through a circular cross-section of radius a.

(a) Find A at a point P located very far from the origin (assume R is so much larger than L that point P may be considered to be at approximately the same distance from every point along the current element).

(b) Determine the corresponding H.