Which of the following is true regarding conductors? O The potential anywhere inside a conductor is always equal to the potential anywhere at the surface of the conductor. O The potential anywhere inside a conductor is always greater than the potential anywhere at the surface of the conductor. O The potential anywhere inside a conductor is always less than the potential anywhere at the surface of the conductor. O The other choices are too vague. More information is needed.

choose the right answer

Pr1. A metal rod having a mass m and length e has resistance R. The rod hangs from two vertical metallic wires of length l in a uni- form vertical magnetic field B of a horseshoe magnet (see figure). The wires have negligib- le resistance. An AC voltage source is connec- ted between the wires which provides a voltage U(t) = Uo cos wt, where Uo and w are constants. U(t) S m IN a) Show that for small angular displacements p the motion of the rod can be described by the cquation U (t) = aö + Bộ + VP, and express the constants a, 3, y in terms of quantities m, l, B, R and the gravitational ac- celeration g. b) At a certain frequency w = wo the ampli- tude of the oscillations of the rod becomes large and the equation above does not describe the motion anymore. Estimate the frequency wo.

1) One theory about charging insulators is called adhesion. Look this up and explain (in about 3-4 sentences) why charge transfers between two insulators that are rubbed together. 2) Describe what happens to the charge on a neutral metal sphere if a charged rod is brought near (but not touching) the sphere. 3) Does the sphere in the previous question remain neutral?