6. A cross section of an infinitely long, conducting cylindrical wire of radius R is as shown in the figure (A). The wire carries a current of uniform density in the positive z-direction. R X R R (B) x (A) (a) [7] Find the direction and magnitude of the magnetic field for the region < Rand r> R, and draw the graph of the magnitude of the field vs r, where is the distance from the central axis of the wire. Another infinitely long, conducting wire of radius with a cylindrical hole of radius R/2 is as shown in the figure (B). The wire carries a current of uniform density in the positive z-direction. (b) [8] Find the direction and magnitude of the magnetic field for the region 0 R on the x-axis, and draw the graph of the magnitude of the field vs xfor x > 0.