Two particles having charges q1 = 0.500 nC and q2 = 8.00 nC. The first charge is located at x=0, y = 3 cm and the second charge is located at x = 5 cm, y = 0. What is the magnitude and direction of the electric field at the origin (x = 0, y = 0)?

Two charged particles are located on the x axis. The first is a charge +Q at x = -a. The second is an unknown charge located at x = +3a. The net electric field these charges produce at the origin has a magnitude of 2k.Q/a?. What are the two possible values of the unknown charge? negative value x Q positive value x Q +

The figure below shows two lines of charge in cross-section coming out of the page. Each line of charge has a linear charge density of ±7.90 nC/cm and they are separated by a distance d = 23.0 cm. What is the magnitude of the electric field at the dot, a point y = 5.80 cm above the midpoint between the lines?

Two charges — q1 = 2.3 × 10-6C, q2 = 5.6 × 10-6C — are separated by a distance of d = 4.75 m.    At what distance, r in meters, from the first charge is the electric field zero?