Test Review Electricity

Transcription

1 Name: Date: 1. An operating television set draws 0.71 ampere of current when connected to a 120-volt outlet. Calculate the time it takes the television to consume joules of electric energy. [Show all work, including the equation and substitution with units.] 4. If a resistor in a parallel branch of a circuit is increased in value, the voltage in that branch of the circuit should A. decrease B. increase C. remain the same 2. The total resistance of the series circuit shown is 15 ohms. What is the resistance of R 2? 5. In the circuit diagram shown, what is the current through the 4.0-ohm resistor? A. less than 5.0 ohms B. 5.0 ohms C. 15 ohms D. 25 ohms A. 1.0 ampere B ampere C. 3.0 amperes D. 48 amperes 3. When three 20-ohm resistors are wired in parallel and connected to a 10-volt source, the total resistance of the circuit will be A. less than 20 ohms B. between 20 and 60 ohms 6. In the circuits represented here, the symbol for the ammeter is A and the symbol for the voltmeter is V. Which diagram represents the proper connections for determining the resistance of the circuit? A. B. C. 60 ohms D. more than 60 ohms C. D. page 1

2 7. As more resistors are added in parallel, the total resistance of a circuit A. decreases B. increases C. remains the same 10. What power is supplied by the source? A W B W C W D. 192 W 8. Three resistors of 20 ohms, 30 ohms, and 60 ohms, respectively, are connected in series with a battery. A current of 2.0 amperes will flow through this circuit when the potential difference of the battery is A. 10 V B. 20 V C. 110 V D. 220 V 11. What is the current in resistor R 2? A A B A C A D A 9. Base your answer(s) to the following question(s) on the diagram given. 12. The diagram shown represents current flowing in branches of an electric circuit. What is the reading on ammeter A? What is the total resistance of the circuit? A Ω B Ω A. 13 A B. 17 A C. 3 A D. 33 A C Ω D Ω page 2

3 13. Which circuit segment has an equivalent resistance of 6 ohms? 15. In which pair of circuits shown could the readings of voltmeters V 1 and V 2 and ammeter A be correct? A. B. C. D. A. A and B B. B and C C. C and D D. A and D 16. Base your answer(s) to the following question(s) on the information and diagram below. 14. Circuit A and circuit B are shown. Compared to the total resistance of circuit A, the total resistance of circuit B is Two parallel plates separated by a distance of meter are charged to a potential difference of 12 volts. An alpha particle with a charge of +2 elementary charges is located at point P in the region between the plates. What is the magnitude and direction of the electric field intensity between the plates. A. less B. the same C. greater A V/m toward plate A B V/m toward plate B C V/m toward plate A D V/m toward plate A page 3

4 17. The accompanying diagram represents a simple electric circuit. 18. Which diagram shows correct current direction in a segment of an electric circuit? A. B. How much charge passes through the resistor in 2.0 seconds? A. 6.0 C B. 2.0 C C. 8.0 C D. 4.0 C C. D. 19. A circuit has a current of 5.0 amperes flowing through it. How long does it take for 30 coulombs of charge to be transferred past a given point in the circuit? A. 5.0 sec B. 6.0 sec C. 35 sec D. 150 sec page 4

5 20. Shown are copper wires of identical cross-sectional area. Which wire will have the least resistance? A. B. C. 23. An electric lamp has a current of 0.50 ampere passing through it when connected to a 120-volt electrical outlet. This lamp will develop a power of A. 5.0 watts B. 60 watts C. 110 watts D. 120 watts D. 21. If the resistance of a circuit is doubled and the voltage remains unchanged, the current flowing in the circuit will be A. one-half as much B. twice as much 24. An electric current of 1 coulomb per second is equal to A. 1 ampere B. 1 volt C. 1 joule D. 1 ohm C. one-fourth as much D. four times as much 22. Eight coulombs of electric charge flow through a wire in two seconds. What is the current? A. 10 amperes B. 2 amperes 25. If the temperature of a current-carrying wire increases, the resistance of the wire A. decreases B. increases C. remains the same C. 8 amperes D. 4 amperes 26. Which segment of copper wire has the highest resistance at room temperature? A. 1.0 m length, m 2 cross-sectional area B. 2.0 m length, m 2 cross-sectional area C. 1.0 m length, m 2 cross-sectional area D. 2.0 m length, m 2 cross-sectional area page 5

6 27. An electrical heater raises the temperature of a measured quantity of water. Six thousand joules of energy is absorbed by the water from the heater in 30.0 seconds. What is the minimum power rating of the heater? 29. Which graph represents a circuit element at constant temperature that obeys Ohm s law? A. B. A W B W C W D W C. D. 28. Which diagram shows the correct current direction in a circuit segment? A. B. 30. A copper wire has a resistance of 200 ohms. A second copper wire with twice the cross-sectional area and the same length would have a resistance of A. 50 Ω B. 100 Ω C. 200 Ω D. 400 Ω C. D. 31. The work required to move a charge of 3.0 coulombs through a potential difference of 12 volts is A joule B. 9 joules C. 36 joules D. 4.0 joules page 6

7 32. The diagram represents two charged parallel plates. How does the intensity of the electric field compare at locations A, B, and C? 34. The diagram shows the electric field in the vicinity of two charged conducting-spheres, A and B. What is the static electric charge on each of the conducting spheres? A. The intensity is greater at A than at B. B. The intensity is greater at C than at A. C. The intensity is greater at B than at C. D. The intensity is the same at A, B, and C. A. A is negative and B is positive. B. A is positive and B is negative. C. Both A and B are positive. D. Both A and B are negative. 35. In the diagram, an electron moving with speed v enters the space between two oppositely charged parallel plates. Which diagram best represents the path the electron follows as it passes between the plates? 33. If 8.0 joules of work is required to transfer 4.0 coulombs of charge between two points, then the potential difference between the two points is A. 6.4 V B. 2.0 V C. 32 V D. 40 V A. B. C. D. page 7

8 36. The diagram shows the initial charge and position of three identical metal spheres, X, Y, and Z, which have been placed on insulating stands. All three spheres are simultaneously brought into contact with each other and then returned to their original positions. Which statement best describes the charge of the spheres after this procedure is completed? 38. Which statement describes the gravitational force and the electrostatic force between two charged particles? A. The gravitational force may be either attractive or repulsive, whereas the electrostatic force must be attractive. B. The gravitational force must be attractive, whereas the electrostatic force may be either attractive or repulsive. C. Both forces may be either attractive or repulsive. A. All the spheres are neutral D. Both forces must be attractive. B. Each sphere has a net charge of coulomb. C. Each sphere retains the same charge that it had originally. D. Sphere Y has a greater charge than spheres X or Z. 39. An electrostatic force exists between two coulomb point charges separated by a distance of meter. As the distance between the two point charges is decreased, the electrostatic force of A. attraction between the two charges decreases B. attraction between the two charges increases C. repulsion between the two charges decreases D. repulsion between the two charges increases 37. An electric field exerts an electrostatic force of magnitude newton on an electron within the field. What is the magnitude of the electric field strength at the location of the electron? A N/C B N/C C N/C D N/C 40. An electric toaster is rated 1200 watts at 120 volts. What is the total electrical energy used to operate the toaster for 30. seconds? A J B J C J D J page 8

9 41. A metal sphere, X, has an initial net charge of coulomb and an identical sphere, Y, has an initial net charge of coulomb. The spheres touch each other and then separate. What is the net charge on sphere X after the spheres have separated? 44. Calculate the rate at which the battery supplies energy to the circuit. [Show all work, including the equation and substitution with units.] A. 0 C B C C C D C 45. If another resistor were added in parallel to the original circuit, what effect would this have on the current through resistor R 1? 42. Base your answer to the following question on the diagram and information below and on your knowledge of physics. A 15-ohm resistor, 30.-ohm resistor, and an ammeter are connected as shown with a 60.-volt battery. 46. Base your answer to the following question on the information and diagram below and on your knowledge of physics. A 12-volt battery causes 0.60 ampere to flow through a circuit that contains a lamp and a resistor connected in parallel. The lamp is operating at 6.0 watts. Using the circuit symbols shown on the Reference Tables for Physical Setting/Physics, draw a diagram of the circuit in the space provided below. Calculate the equivalent resistance of R 1 and R 2. [Show all work, including the equation and substitution with units.] 47. Calculate the current through the lamp. 48. Determine the current in the resistor. 43. Determine the current measured by the ammeter. 49. Calculate the resistance of the resistor. page 9

10 50. Base your answer(s) to the following question(s) on the information and diagram below and on your knowledge of physics. Two conducting parallel plates meter apart are charged with a 12-volt potential difference. An electron is located midway between the plates. The magnitude of the electrostatic force on the electron is newton. 53. Describe what happens to the magnitude of the net electrostatic force on the electron as the electron is moved toward the positive plate. 54. Base your answer(s) to the following question(s) on the information and circuit diagram below and on your knowledge of physics. Three lamps are connected in parallel to a 120.-volt source of potential difference, as represented below. On the diagram provided, draw at least three field lines to represent the direction of the electric field in the space between the charged plates. Calculate the resistance of the 40.-watt lamp. [Show all work, including the equation and substitution with units.] 55. Describe what change, if any, would occur in the power dissipated by the 100.-watt lamp if the 60.-watt lamp were to burn out. 51. Identify the direction of the electrostatic force that the electric field exerts on the electron. 56. Describe what change, if any, would occur in the equivalent resistance of the circuit if the 60.-watt lamp were to burn out. 52. Calculate the magnitude of the electric field strength between the plates, in newtons per coulomb. [Show all work, including the equation and substitution with units.] 57. The circuit is disassembled. The same three lamps are then connected in series with each other and the source. Compare the equivalent resistance of this series circuit to the equivalent resistance of the parallel circuit. page 10