1 ALABAMA SCHOOL OF FINE ART, 8 TH GRADE HONORS PHYSICS QUIZ 4-18-2016: ELECTROSTATICS TIME: 90 MINUTES NAME COVERAGE: ELECTRIC CHARGE, ELECTROSTATIC FORCE (COULOMB S LAW ), ELECTRIC POTENTIAL, ELECTRIC FIELD, PARALLEL PLATES, CAPACITORS INSTRUCTIONS: ANSWER ALL QUESTIONS. YOU MAY USE YOUR AP-1/AP-2 PHYSICS EQUATION SHEET FOR RELEVANT EQUATIONS AND CONSTANTS CIRCLE YOUR ANSWER IN THE QUESTION PAPER. YOU MUST ALSO SHADE YOUR CHOICE IN THE SCANTRON PAPER. SHOW CALCULATIONS WHEN POSSIBLE ELECTRIC CHARGE 1. Metal sphere A has a charge of -2 units and an iden- tical metal sphere, B, has a charge of - 4 units. If the spheres are brought into contact with each other and then separated, the charge on sphere B will be A. 0 units B. -2 units C. -3 units D. +4 units 2. Oil droplets may gain electrical charges as they are projected through a nozzle. Which quantity of charge is not possible on an oil droplet? A. 8.0 10-19 C B. 4.8 10-19 C C. 3.2 10-19 C D. 2.6 10-19 C 3. Two identically-sized metal spheres, A and B, are on insulating stands, as shown in the diagram below. Sphere A possesses an excess of 6.3 1010 electrons and sphere B is neutral. Which diagram best represents the charge distribution on sphere B?
2 4) A dry plastic rod is rubbed with wool cloth and then held near a thin stream of water from a faucet. The path of the stream of water is changed, as represented in the diagram below. Which force causes the path of the stream of water to change due to the plastic rod? A. nuclear B. magnetic C. electrostatic D. gravitational 5. When a neutral metal sphere is charged by contact with a positively charged glass rod, the sphere A. loses electrons B. gains electrons C. loses protons D. gains protons 6. A negatively charged plastic comb is brought close to, but does not touch, a small piece of paper. If the comb and the paper are attracted to each other, the charge on the paper A. may be negative or neutral B. may be positive or neutral C. must be negative D. must be positive 7. A positively charged glass rod attracts object X. The net charge of object X A. may be zero or negative B. may be zero or positive C. must be negative D. must be positive
3 8. A positive test charge is placed between an electron, e, and a proton, p, as shown in the diagram below. When the test charge is released, it will move toward A. A B. B C. C D. D ELECTROSTATIC FORCE: 9 Which graph best represents the electrostatic force between an alpha particle with a charge of +2 elementary charges and a positively charged nucleus as a function of their distance of separation? 10. In the diagram below, two positively charged spheres, A and B, of masses ma and mb are located a distance d apart. Which diagram best represents the directions of the gravitational force, Fg, and the electrostatic force, Fe, acting on sphere A due to the mass and charge of sphere B? [Vectors are not drawn to scale.]
4 11. Which graph best represents the relationship between the magnitude of the electrostatic force and the distance between two oppositely charged particles? 12. The distance between an electron and a proton is varied. Which pair of graphs best represents the relationship between gravitational force, Fg, and distance, r, and the relationship between electrostatic force, Fe, and distance, r, for these particles?
5 13. A balloon is rubbed against a student s hair and then touched to a wall. The balloon sticks to the wall due to (A) electrostatic forces between the particles of the balloon (B) magnetic forces between the particles of the wall ( C ) electrostatic forces between the particles of the balloon and the particles of the wall (D)magnetic forces between the particles of the balloon and the particles of (14) Two electrons are separated by a distance of 3.00 10-6 meter. What are the magnitude and direction of the electrostatic forces each exerts on the other? (A) 2.56 10-17 N away from each other (B) 2.56 10-17 N toward each other (C) 7.67 10-23 N away from each other (D) 7.67 10-23 N toward each other 15. The diagram represents two small, charged, identical metal spheres, A and B, that are separated by a distance of 2.0 meters. What is the magnitude of the electrostatic force exerted by sphere A on sphere B? 7.2 10-3 N A. 7.2 10-3 N B. 3.6 10-3 N C. 8.0 10-13 N D. 4.0 10-13 N
6 Electric Fields: 16. Which diagram represents the electric field lines between two small electrically charged spheres? 17. Which graph best represents the relationship between the magnitude of the electric field strength, E, around a point charge and the distance, r, from the point charge? 18. The diagram below represents an electron within an electric field between two parallel plates that are charged with a potential difference of 40 volts. If the magnitude of the electric force on the electron is 2.00 10-15 newton, the magnitude of the electric field strength between the charged plates is A. 3.20 10-34 N/C B. 2.00 10-14 N/C C. 1.25 104 N/C D. 2.00 1016 N/C 19. An electron is located in the electric field between two parallel metal plates as shown in the diagram below.
7 If the electron is attracted to plate A, then plate A is charged? A. positively, and the electric field is directed from plate A toward plate B B. positively, and the electric field is directed from plate B toward plate A C. negatively, and the electric field is directed from plate A toward plate B D. negatively, and the electric field is directed from plate B toward plate A 20. The diagram below shows a beam of electrons fired through the region between two oppositely charged parallel plates in a cathode ray tube. After passing between the charged plates, the electrons will most likely travel path 1. A 2. B 3. C 4. D 21. Two parallel metal plates are connected to a variable source of potential difference. When the potential difference of the source is increased, the magnitude of the electric field strength between the plates increases. The diagram below shows an electron located between the plates. Which graph represents the relationship between the magnitude of the electrostatic force on the electron and the magnitude of the electric field strength between the plates?
8 22. A beam of electrons is directed into the electric field between two oppositely charged parallel plates, as shown in the diagram below. The electrostatic force exerted on the electrons by the electric field is directed A. into the page B. out of the page C. toward the bottom of the page D. toward the top of the page 23. What is the magnitude of the electric field intensity at a point where a proton experiences an electrostatic force of magnitude 2.30 10-25 newton? A 3.68 10-44 N/C B 1.44 10-6 N/C C 3.68 106 N/C D 1.44 1044 N/C 24. In the diagram below, P is a point near a negatively charged sphere. Which vector best represents the direction of the electric field at point P?
9 25 An object with a net charge of 4.80 10-6 coulomb experiences an electrostatic force having a magnitude of 6.00 10-2 newton when placed near a negatively charged metal sphere. What is the electric field strength at this location? A. 1.25 10 4 N/C directed away from the sphere B. 1.25 10 4 N/C directed toward the sphere C. 2.88 10-8 N/C directed away from the sphere D. 2.88 10-8 N/C directed toward the sphere 26 The diagram below represents the electric field surrounding two charged spheres, A and B. What is the sign of the charge of each sphere? A. Sphere A is positive and sphere B is negative B. Sphere A is negative and sphere B is positive C. Both spheres are positive D. Both spheres are negative 27. Which diagram represents the electric field between two oppositely charged conducting spheres? 28. An moving electron is deflected by two oppositely charged parallel plates, as shown in the diagram below. The electric field between the plates is directed from a. A to B (c) B to A b. C to D (d) D to C
10 29. An object with a net charge of 4.80 10-6 coulomb experiences an electrostatic force having a magnitude of 6.00 10-2 newton when placed near a negatively charged metal sphere. What is the electric field strength at this location? 1.25 104 N/C directed away from the sphere 1.25 104 N/C directed toward the sphere 2.88 10-8 N/C directed away from the sphere 2.88 10-8 N/C directed toward the sphere Electric Potential: 30. If 1.0 joule of work is required to move 1.0 coulomb of charge between two points in an electric field, the potential difference between the two points is A. 1.0 10 0 V B. 9.0 10 9 V C. 6.3 10 18 V D. 1.6 10-19 V 31. The diagram below represents a positively charged particle about to enter the electric field between two oppositely charged parallel plates. The electric field will deflect the particle A. into the page B. out of the page C. toward the top of the page D. toward the bottom of the page 32. What is the total amount of work required to move a proton through a potential difference of 100 volts? A. 1.60 10-21 J B. 1.60 10-17 J C. 1.00 10 2 J D. 6.25 10 20 J 33. Which electrical unit is equivalent to one joule? A. volt per meter (C) ampere volt B. volt per coulomb (D ) coulomb volt
11 34. If 60 joules of work is required to move 5.0 coulombs of charge between two points in an electric field, what is the potential difference between these points? A. 5.0 V B. 12 V C. 60 V D. 300 V 35. A potential difference of 10 volts exists between two points, A and B, within an electric field. What is the magnitude of charge that requires 2.0 10-2 joule of work to move it from A to B? A. 5.0 102 C B. 2.0 10-1 C C. 5.0 10-2 C D. 2.0 10-3 C 36. The diagram below represents a source of potential difference connected to two large, parallel metal plates separated by a distance of 4.0 10-3 meter. Which statement best describes the electric field strength between the plates? 1. It is zero at point B 2. It is a maximum at point B 3. It is a maximum at point C 4. It is the same at points A, B, and 37. The electronvolt is a unit of A. energy B. charge C. electric field strength D. electric potential difference 38. Parallel conducting plates separated by an insulator can be used to store electrical charge. These devices come in a variety of sizes, and are known as? (a) (b) (c) (d) (e) Capacitors Resistors Inductor Transistor Electric Field
12 39. Capacitance C in Farads (F) is defined as charge in coulomb (Q) / potential difference in volt (V). A capacitor stores 3 microcoulombs of charge with a potential difference of 1.5 volts across the plates. What is the capacitance C of this capacitor? A. 2 * 10 ^-6 Farads B. 4 * 10 ^-6 Farads C. 2 * 10 ^-10 Farads D. 4 * 10 ^-10 Farads 40. Capacitance between two plates depend on area (A) and separation distance (d) as shown in the diagram below. (a) (b) (c) (d) (e) Find the capacitance of two parallel plates of length 1 millimeter and width 2 millimeters if they are separated by 3 micrometers of air. 8.6 * 10^-12 F 5.9 * 10^-12 F 12.8 * 10^-12 F 5.9 * 10^12 F 5.9 F