rubs a piece of fur on a hard rubber rod, giving the rod a negative charge. What happens? a. Protons are removed from the rod. b. Electrons are added to the rod. c. The fur is also charged negatively. d. The fur is left neutral.

A point particle with a positive charge, q, and a mass, m, is held stationary by the forces of gravity and electricity above an infinite, thin, planar sheet of positive charge with charge density σ. What is the value of σ?     a. qmε0/gr2   b. qε0/mgr2   c. ε0mg/q   d. 2qε0/mg   e. 2ε0mg/q

In a region of space, an electric field of magnitude, E, is pointing in the positive x direction. A charge of -4q0 is released from rest on the x-axis. what is the direction of its motion and how is its acceleration calculated? A. In the negative x-direction with an acceleration of 4q0E/m. B. In the positive y-direction with an acceleration of q0E. C. In the positive x-direction with an acceleration of 4q0E/m. D. In the negative x-direction with an acceleration of q0E.

40. Two metal spheres are resting on insulating stands. Sphere A has a net positive charge, and sphere B is neutral. The two spheres are brought into contact with each other, and then are separated. Which describes the transfer of charge between Sphere A and B, and the final result of net charges after they are separated? A.Positive charges move from Sphere A onto Sphere B, resulting in both Sphere A and Sphere B having net positive charge. B. Positive charges move from Sphere B onto Sphere A, resulting in both Sphere A and Sphere B having net positive charge. C.Negative charges move from Sphere A onto Sphere B, resulting in both Sphere A and Sphere B having net negative charge. D.Negative charges move from Sphere B onto Sphere A, resulting in both Sphere A and Sphere B having net positive charge.