ADDITIONS TO PROBLEMS and PROBLEMS FROM HRW SUPPLEMENT #1 JULY 15 - JULY 21 Correction to HRW CHAPTER 28, #33. EMF2 in the figure for that problem should be drawn from the negative side of the battery to the positive side. Battery EMF's always go from negative to positive. Problems from HRW Problem Supplement #1 (6th edition) CHAPTER 25 58. Consider a flat, nonconducting ring of outer radius R and inner radius r = 0.200R; the ring has a uniform charge per unit area of sigma. With V = 0 at infinity, find an expression for the electric potential at point P on the central axis of the ring, at a distance z = 2.00R from the center of the ring. CHAPTER 26 53. A certain parallel-plate capacitor is filled with a dielectric for which Kappa = 5.5. The area of each plate is 0.034 m^2, and the plates are separated by 2.0 mm. The capacitor will fail (short out and burn up) if the electric field between the plates exceeds 200 kN/C. What is the maximum energy that can be stored in the capacitor? 66. Two parallel-plate capacitors A and B are connected in parallel across a 600 V battery. Each plate has area 80.0 cm^2 and the plate separations are 3.0 mm. Capacitor A is filled with air; capacitor B is filled with a dielectric of dielectric constant Kappa = 2.60. Find the magnitude of the electric field within (a) the dielectric of capacitor B and (b) the air of capacitor A. What are the free charge densities sigma on the higher-potential plate of (c) capacitor A and (d) capacitor B? (e) What is the induced charge density sigma' on the surface of the dielectric which is nearest to the higher-potential plate of capacitor B. 74. The figure for this problem is Fig. 26-17, with the dielectric in that figure being replaced with a piece of copper. A slab of copper of thickness b is thrust into a parallel-plate capacitor of plate area A; it is exactly halfway between the plates. (a) What is the capacitance after the slab is introduced? (b) If a charge q is maintained on the plates, what is the ratio of the stored energy before to that after the slab is inserted? (c) How much work is done on the slab as it is inserted? Is the slab sucked in or must it be pushed in?