(1) Two point charges, Q1 = +2 x 10-6 C and Q2 = -3 x 10-6 C, are situated as shown.
(a) Find the electric potential at point A and at point B.
(b) Find the work needed to move a point charge Q3 = 5 x 10-6 C from point A to point B along the curved path shown by the solid line
(2) A solid, insulating sphere of radius a has a uniform charge density ρ and a total charge +Q. Find the magnitude of the electric field in the regions ra . Draw the schematic graph of electric field (E vs. r).