2. Shown below is the cross-section of two large parallel plates carrying charges +Q (top) and -Q (bottom). Each plate has area A. Vertically between the plates, a small charged particle with charge q and mass m is suspended at y=d/2, i.e. the force of gravity FG = -mg and the electrostatic force on the particle cancel. Recall that the electric field between large, oppositely charged plates of uniform charge density is E = o/e, where o is the charge per unit area. a. What is the sign of the charge q? b. Determine q in terms of the other quantities given. c. Draw at least two equipotential lines on the figure and label the direction of increasing potential. d. If the charge q moves from y=0 to y=d, does it gain or lose potential energy? Explain.

2. Shown below is the cross-section of two large parallel plates carrying charges +Q (top) and -Q (bottom). Each plate has area A. Vertically between the plates, a small charged particle with charge q and mass m is suspended at y=d/2, i.e. the force of gravity FG = -mg and the electrostatic force on the particle cancel. Recall that the electric field between large, oppositely charged plates of uniform charge density is E = o/e, where o is the charge per unit area. a. What is the sign of the charge q? b. Determine q in terms of the other quantities given. c. Draw at least two equipotential lines on the figure and label the direction of increasing potential. d. If the charge q moves from y=0 to y=d, does it gain or lose potential energy? Explain.