12. There are two infinite plates with surface area charge densities of +4 and arranged as shown. What is the electric field, magnitude and direction, at point P?
+40
+a
A. 10Ka to the left
B. 10Ko to the right
C. 6Ka to the left
D. 6Ko to the right
E. 5Ko to the left
13. Two plates having equal magnitude and opposite sign charges are positioned as shown. An electron placed at point P will feel a force in what direction?
A. -y axis
B. -x axis
C. +x axis
D. -z axis
E. -x axis