**Unformatted text preview:**

A: E=0, V=0, =0 E: E=constant, V=0, =0E: EIII > EI > EIIF: EIII > EII > EIE: at the outside surfaceF: beyond the outside surfaceG: infinitely far away from the sphereE: VA = (1/4)VBF: Cannot be compared without knowing the amount of charge on each sphereName _________________________Phys212 Test I, Fall 2004For #3-#7, circle the best answer. (4 pts each, no partial credit) 1. Two electric charges of –Q, and +Q are arrangedas shown in the figure. What is the direction of the electric field at point P?answer:A: E: B: F: C: G: D: H: 2. Eight coulombs of charge is spread uniformly throughout a box measuring 2m x 1m x 2m. What is the most appropriate charge density to describe this cube?answer:A: = 2 C/m3D: = 8 C G: = 32 Cm3B: = 2 C/m3E: = 8 C H: = 32 Cm3C: = 2 C/m3F: = 8 C I: = 32 Cm33. Within the volume of a conductor, which of the following is true about the electric field (E), electric potential (V), and charge density within the conductor ()?answer:A: E=0, V=0, =0 E: E=constant, V=0, =0B: E=0, V=0, =constant F: E=constant, V=0, =constantC: E=0, V=constant, =0 G: E=constant, V=constant, =0D: E=0, V=constant, =constant H: E=constant, V=constant, =constant4. Two charges are fixed in the positions shown. Where could a third charge be placed so that it has no netforce acting on it? region C (center) region A region B region D region E -2 nC -5nC answer:A B C D E P -Q +Q5. In the figure below a positive charge of Q lies at the center of an uncharged conductor. Rank the electric fields in each of the three locations in order of increasing E-field magnitude.answer:A: EI > EII > EIIIB: EI > EIII > EIIC: EII > EI > EIIID: EII > EIII > EIE: EIII > EI > EIIF: EIII > EII > EI6. Consider a hollow conducting sphere which has a total charge of –Q. Where is the electric potential equal to zero?A: directly at the centerB: between the center and the inside surfaceC: at the inside surfaceD: inside the conductor (between the inside and outside surfaces)E: at the outside surfaceF: beyond the outside surfaceG: infinitely far away from the sphere7. Two charged conducting spheres of different size are attached using a thin conducting wire. Compare the electric potential of the two spheres:answer:A: VA = 4VBB: VA = 2VBC: VA = VBD: VA = (1/2)VBE: VA = (1/4)VBF: Cannot be compared without knowing the amount of charge on each sphere Q I II IIIShow your work and/or explain your answers.You should draw a meaningful figure for ALL problems.Make sure you answer the question and use appropriate units if needed!!!(11pts) (similar to example #9)8. A charge is uniformly distributed along a line of length L such that the charge density is . What is the x-component of the electric field at the point indicated below? Express your answer in terms of , L, s and any needed constants. y P x s L(11pts) (P21.98)9. Electric charge is distributed uniformly along two sides of a square. One side has a linear charge density of and the other side has a charge density of -. The square has sides of length w. Find the x- and y- components of the electric field at the center of the square. y -Q x R -(11pts) (example #27)10. A line charge of -2 nC/m lies along the axis of an infinite conducting hollow cylinder shell of inner radius 2 cm and outer radius 3 cm. A charge density of +4 nC/m lies on the conducting hollow cylinder. Find the electric field at a distance of 5 cm from the axis.(11pts) (similar to example #36 & P23.67)11. An object with a charge of 3 C and a mass of 7 g is initially located on the axis of a ring but very far from the center of the ring. The ring is fixed in space and has a charge of 12 mC and a radius of 11 cm. If the object is given n initial speed toward the center of the ring of 900 m/s, how close to the center of the ring will the object

View Full Document