a. A positively charged sheet has a surface charge density of o = 2 uC/m 2. What are the magnitude and direction of the electric field at a point 4 cm above the sheet? X b. A second sheet is placed 10 cm above the bead. The net electric field at the point is now 0.678 x 10 6 N/C pointing upwards. What is the charge density on the second sheet? c. Using your results from (b), what is the electric field (magnitude and direction) at a point 4 cm above the second sheet as shown on the right