An infinite sheet of charge, oriented perpendicular to the x-axis, passes through x = 0. It has a surface charge density 01 = -2.1 pC/mz. A thick, infinite conducting slab, also oriented perpendicular to the xaxis occupiees the region between a = 2.1 cm and b = 4.2 cm. The conducting slab has a net charge per unit area of 02 = 74 pClmZ