Q31:Figure P30.31 is a cross-sectional view of a coaxial cable. The center conductor is surrounded by a rubber layer, an outer conductor, and another rubber layer. In a particular application, the current in the inner conductor is I1= A out of the page and the cur- rent in the outer conductor is I 2 = A into the page. Assuming the distance d = mm, determine the magnitude and direction of the magnetic field at
(a) point a and
(b) point b.