B(z): = Holcos e 4 (CO6) 27 2 R = R 2 (R2+22)3/2 z4 z=0 (5.41) FIGURE 5.59 Problem 5.47 The magnetic field on the axis of a circular current loop (Eq. 5.41) is far from uniform (it falls off sharply with increasing z). You can produce a more nearly uniform field by using two such loops a distance d apart (Fig. 5.59). (a) Find the field (B) as a function of z, and show that B/az is zero at the point midway between them (z = 0). Solve the issue by "multipole expansion"