A conducting sphere has a net charge of -q and of mass m is suspended from the ceiling by a light string. A uniform electric field E is applied vertical down on the sphere.If m = 1 g, q = 1 μC, and E = 5000 N/C, the tension T in the string is

Question

Quizplus · Accepted Answer

The net force on the sphere is the gravitational force minus the electric force:
Fnet = mg - qE
Plugging in the values given, we get:
Fnet = (0.001 kg)(9.81 m/s^2) - (1 × 10^-6 C)(5000 N/C) = 4.81 × 10^-3 N
Since the sphere is suspended by a string, the tension in the string must balance the net force:
T = Fnet = 4.81 × 10^-3 N

A Conducting Sphere Has a Net Charge of -Q and of Mass