Sas Phys513 Mc2 Teacher Answer Key May 24, 2013

1 1. The half-life of a radioactive nuclide is 6 hours. After one day (24 hours), approximately how much of an original 2.4 X 10-2-kilogram sample of this nuclide remains? 1. 1.5 X 10-3 kg 3. 4.0 X 10-3 kg 2. 2.4 X 10-3 kg 4. 6.0 X 10-3 kg

1 2. The work function for a copper surface is 7.3 x 10-19 joule. If photons with an energy of 9.9 x 10-

19 joule are incident on the copper surface, the maximum kinetic energy of the ejected photoelectrons is 1. 2.6 x 10-19 J 3. 9.9 x 10-19 J 2. 7.3 x 10-19 J 4. 1.7 x 1030 J No Explanation Available. 3 3. If the momentum a a particle is 1.8 x 10-22 kilogram-meter/second, its matter wavelength is approximately 1. 1.2 x 10 -55 m 3. 3.7 x 10 -12 m 2. 2.7 x 10 11 m 4. 5.0 x 10-7 m No Explanation Available. 2 4. When a 2.0-meter-tall object is placed 4.0 meters in front of a lens, an image is formed on a screen located 0.050 meter behind the lens. What is the size of the image?

1. 0.10 m 3. 2.5 m 2. 0.025 m 4. 0.40 m No Explanation Available. 2 5. The diagram represents wave movement. Which two points are in phase?

1. A and G 3. C and E 2. B and F 4. D and F No Explanation Available. 4 6. Base your answer to the following question on the information and diagram. Two parallel plates separated by a distance of 1.0 X 10-3 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?

1. 1.2 X 103 V/m toward plate A 3. 1.2 X 104 V/m toward plate A 2. 1.2 X 103 V/m toward plate B 4. 1.2 X 104 V/m toward plate B

1 7. A 12-volt automobile battery has 8.4 X 103 coulombs of electric charge. The amount of electrical energy stored in the battery is approximately 1. 1.0 X 105 J 3. 7.0 X 102 J 2. 8.4 X 103 J 4. 1.4 X 10-3 J

2 8. An alpha particle consists of two protons and two neutrons. The alpha particle's charge of +2 elementary charges is equivalent to 1. 8.0 X 10-20 C 3. 1.2 X 1019 C 2. 3.2 X 10-19 C 4. 3.2 X 1019 C

4 9. An electric fan draws 1.7 amperes of current when operated at a potential difference of 120 volts. How much electric energy is needed to run this fan for 1 hour? [1 hour=3600 seconds] 1. 7.1 X 101 J 3. 2.5 X 115 J 2. 2.0 X 102 J 4. 7.3 X 105 J No Explanation Available. 2 10. Base your answer on the diagram which represents an electron about to enter uniform magnetic field B. The velocity of the electron (v) is 6.0 x 107 meters per second to the right.The flux density of the magnetic field is 4.0 x 10-2 telsa, directed into the page. The magnitude of the magnetic force acting on the electron in the field is approximately

1. 2.4 x 10-11 N 3. 1.6 x 1--18 N 2. 3.8 x 10-13 N 4. 2.2 x 10-24 N No Explanation Available. 1 11. A person is standing in front of a diverging (convex) mirror. What type of image does the mirror form of the person? 1. erect, virtual, and smaller than the person 3. erect, real, and smaller than the person 2. erect, virtual, and the same size as the person 4. erect, real, and the same size as the person

1 12. The accompanying diagram represents the magnetic lines of force around a bar magnet. At which point is the magnitude of the magnetic field strength of the bar magnet the greatest?

1. A 3. C 2. B 4. D

1 13. Electrostatic force F exists between two point charges. If the distance between the charges is tripled, the force between the charges will be 1. F/9 3. 3F 2. F/3 4. 9F

3 14. The diagram represents magnetic lines of force within a region of space.

1. A 3. C

2. B 4. D

2 15. A wire conductor is moved at constant speed perpendicularly to a uniform magnetic field. If the strength of the magnetic field is increased, the induced potential across the ends of the conductor 1. decreases 3. remains the same 2. increases

3 16. In the currently accepted model of the atom, a fuzzy cloud around a hydrogen nucleus is used to represent the 1. electron's actual path, which is not a circular orbit

3. general region where the atom's electron is most probably located

2. general region where the atom's proton is most probably located 4. presence of water vapor in the atom

4 17. A light spring is attached to a heavier spring at one end. A pulse traveling along the light spring is incident on the boundary with the heavier spring. At this boundary, the pulse will be 1. totally reflected 3. totally transmitted into the heavier spring

2. totally absorbed 4. partially reflected and partially transmitted into the heavier spring

3 18. The distance between successive antinodes in the standing wave pattern shown is equal to

1. 1 wavelength 3. 1/2 wavelength 2. 2 wavelengths 4. 1/3 wavelength No Explanation Available. 4

19. In a nondispersive medium, the speed of a light wave depends on 1. its wavelength 3. its frequency 2. its amplitude 4. the nature of the medium No Explanation Available. 1 20. The 100% efficient transformer in the diagram has three turns in its primary coil and nine turns in its secondary coil. When a 12-volt alternating current source is connected to the primary coil, 3.0 amperes flows in the primary coil. What potential difference and current are induced in the secondary coil?

1. 36 V and 1.0 A 3. 4.0 V and 1.0 A 2. 36 V and 9.0 A 4. 4.0 V and 9.0 A No Explanation Available. 1 21. A plane mirror will form an image that is 1. virtual and erect 3. virtual and inverted 2. real and inverted 4. real and erect No Explanation Available. 4 22. Which characteristics best describe the image produced by a plane mirror? 1. real and inverted 3. virtual and inverted 2. real and erect 4. virtual and erect

1 23. In nuclear reactors, neutrons are slowed down by 1. moderators 3. fuel rods 2. control rods 4. accelerators No Explanation Available. 4 24. The diagram shows an antenna emitting an electromagnetic wave.

1. by remaining stationary 3. by moving at constant speed downward, only

2. by moving at constant speed upward, only 4. by accelerating alternately upward and downward

1 25. Two points on a traverse wave that have the same magnitude of displacement from equilibrium are in phase if the points also have the 1. same direction of displacement and the same direction of motion

3. opposite direction of displacement and the same direction of motion

2. same direction of displacement and the opposite direction of motion

4. opposite direction of displacement and the opposite direction of motion

No Explanation Available. 4 26. Electromagnetic waves can be generated by accelerating 1. a hydrogen bomb 3. a neutron 2. a photon 4. an electron No Explanation Available. 3 27. A spherical concave mirror is used in the back of a car headlight. Where must the bulb of the headlight be located to produce a parallel beam of reflected light? 1. between the principal focus and the mirror 3. at the principal focus of the mirror 2. beyond the center of curvature of the mirror 4. at the center of curvature of the mirror No Explanation Available. 2 28. Light is to brightness as sound is to

1. color 3. period 2. loudness 4. speed No Explanation Available. 1 29. The diagram shows an electron current in a wire loop. What is the direction of the magnetic field at the center of the loop?

1. out of the page 3. clockwise 2. into the page 4. counterclockwise No Explanation Available. 2 30. In the reaction

1. positive electron 3. proton 2. negative electron 4. neutron

4 31. Which process occurs as nitrogen nuclei are bombarded by alpha particles to produce an isotope of oxygen? 1. photoelectric emission 3. fission 2. thermionic emission 4. transmutation

4 32. Base your answer to the following question on the information and diagram What is the distance from the lens to the candle's image?

1. 0.10 m 3. 0.40 m 2. 0.30 m 4. 0.60 m

4 33. A lens forms a real image three times the size of the object when the image is 0.12 meter from the lens. How far from the lens is the object? 1. 0.36 m 3. 0.03 m

2. 0.09 m 4. 0.04 m No Explanation Available. 1 34. Base your answer on the diagram which shows a parked police car with a siren on top. The siren is producing a sound with a frequency of 680 hertz, which travels first through point A and then through point B, as shown.The speed of sound is 340 meters per second. What is the wavelength of the sound produced by the car's siren?

1. 0.50 m 3. 2.3 X 10^5 m 2. 2.0 m 4. 2.3 x 10^-6 m No Explanation Available. 2 35. The driver of a car blows the horn as the car approaches a crosswalk. Compared to the actual pitch of the horn, the pitch observed by a pedestrian in the crosswalk is 1. lower 3. the same 2. higher

3 36. The diagram shows a person shaking the end of a rope up and down, producing a disturbance that moves along the length of the rope.

1. torsional 3. transverse 2. longitudinal 4. elliptical

1 37. Which optical device causes parallel light rays to diverge?

1. convex mirror 3. plane mirror 2. concave mirror 4. convex lens

2 38. A wave generator located 4.0 meters from a reflecting wall produces a standing wave in a string, as shown in the diagram.

1. 0.40 Hz 3. 10. Hz 2. 5.0 Hz 4. 40. Hz

2 39. Which diagram best represents image I, which is formed by placing object O in front of a plane mirror?

4 40. Moving a point charge of 3.2 x 10-19 coulomb between points A and B in an electric field requires 4.8 x 10-19 joule of energy. What is the potential difference between these two points? 1. 0.67 V 3. 3.0 V 2. 2.0 V 4. 1.5 V No Explanation Available. 3 41. Moving 2.0 coulombs of charge a distance of 6.0 meters from point A to point B within an electric field requires a 5.0-newton force. What is the electric potential difference between points A and B? 1. 60. V 3. 15 V 2. 30. V 4. 2.5 V

4

42. In the accompanying diagram, two identical spheres, A and B, have equal net positive charges. Which arrow best represents the direction of their resultant electric field at point P?

2 43. If the potential drop across an operating 300.-watt floodlight is 120 volts, what is the current through the floodlight? 1. 0.40 A 3. 7.5 A 2. 2.5 A 4. 4.8 A No Explanation Available. 1 44. Base your answer on the accompanying diagram, which shows two resistors connected in parallel across a 6.0-volt source. Compared to the power dissipated in the 1.0-ohm resistor, the power dissipated in the 3.0-ohm

resistor is (note that this question has only three choices)

1. less 3. the same 2. greater

2 45. Two oppositely charged parallel plates are a fixed distance apart. Which graph best represents the relationship between the electric field intensity (E) between the plates and the potential difference (V) across the plates?

3 46. The diagram represents an electric circuit. The total amount of energy delivered to the resistor in 10. seconds is

1. 3.2 J 3. 20. J 2. 5.0 J 4. 320 J

2 47. Base your answer on the accompanying diagram, which shows two resistors and three ammeters connected to a voltage source. What is the current reading of ammeter A1?

1. 10.0 A 3. 3.0 A 2. 6.0 A 4. 4.0 A

2

48. Which diagram best represents to magnetic field near a bar magnet?

1. 1 3. 3 2. 2 4. 4 No Explanation Available. 1 49. Base your answer on the information and the data table. During a laboratory investigation of transformers, a group of students obtained the following data during four trials, using a different pair of coils in each trial. What is the ratio of the number of turns in the primary coil to the number of turns in the secondary coil in trial 3?

1. 1:6 3. 6:1 2. 1:9 4. 9:1 No Explanation Available. 2 50. In the transmutation reaction what is particle X?

1. 1 3. 3 2. 2 4. 4

No Explanation Available.