1. Two charged particles are fixed on the x-axis. Particle 1 of charge q1 = 2.1 x 10-8 C is at position x = 20 cm and particle 2 of charge q2 = -4 q1 is at position x = 70 cm. At what coordinate on the axis (other than infinity) is the net electric field produced by the two particles equal to zero?
2. A charge of q1 = 6.0 uC is locate at (0m, 12m) and a charge q2 = 15 UC is placed at (8.0 m, 0.0m). Calculate the magnitude and direction of the electric field at the origin (0,0).
3. Charge is uniformly distributed around a ring of radius 2.4 cm. The resulting electric field E is measured along the ring's central axis (perpendicular to the plane of the ring). At what distance from the ring's center is E maximum?