PHS 212 Midterm, Fall 2003

NDU PHS 212 - Electricity & Magnetism Faculty of Natural and Applied Sciences Midterm Exam - Fall 2003 Department of Sciences Duration: 2 hours Solve all problems 1. Two charges g and —2g are located above a grounded infinite conducting plane, as shown in the figure. Find the potential V for the space above the plane, -and the charge distribution on the surface of the plane. Vesey RK 2. An infinite cylinder of radius R carries a volume charge distribution p=py(1—=) » where Po is constant. a. Find the electric field inside and outside of the cylinder. _ b, Find the potential difference between the axis and the surface of the cylinder. 3. A spherical capacitor is made from a metallic sphere of radius 0.5 cm and a metallic shell of radius 0.53 cm. The charge on the capacitor is 0.2 uC. a. Find the potential difference between the plates of the capacitor. b. Find the force per unit area f, exerted on the on the surface of the sphere, and f, exerted on the shell. 4. In a given region of space, the electric field in spherical coordinates is given by E= =[2arsin29(1-)+bcos(1— er)Je"F+{ F00820)e" “6—( sing)e “dp = where a, 6 and c are constants. a. Show that this is a valid expression for an electric field b. Find an expression for the potential V. c. Find the charge density in that region.