# Indicate whether the sentence or statement is true or false. The base unit for hertz (Hz) is s

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True/False

Indicate whether the sentence or statement is true or false.

____ 1. The base unit for hertz (Hz) is s–1.

____ 2. When two waves are in phase, they only need to have the same speed.

____ 3. In a transverse wave, the particles in the medium move in a direction perpendicular to the direction of the wave.

____ 4. In a longitudinal wave, the particles in the medium move in a direction perpendicular to the direction of the wave.

____ 5. A trough is a negative pulse which occurs in a longitudinal wave.

____ 6. A crest is a positive pulse which occurs in a transverse wave.

____ 7. All periodic waves originate from a vibrating source that determines the frequency of the wave.

____ 8. The universal wave equation can be used to calculate the amplitude of a wave.

____ 9. Whenever a wave changes mediums, some of the energy is reflected back as a partial reflection whose phase depends on the relative speed of the wave in the two mediums.

____ 10. When a student sends a positive pulse towards the fixed-end of a spring, the reflected pulse returns as a negative pulse.

____ 11. When a student sends a positive pulse towards the free-end of a spring, the reflected pulse returns as a negative pulse.

____ 12. The normal is a line drawn perpendicular to the wavefront of a transverse wave.

____ 13. The angle of incidence of a wave striking a barrier can be measured from the wavefront to the barrier's surface.

____ 14. Constructive interference occurs when two like pulses meet, or act simultaneously on the same particles of a medium.

____ 15. Destructive interference in a longitudinal wave occurs when two compressions meet, or act simultaneously on the same particles of a medium.

____ 16. A supercrest is formed when a very large amplitude oscillation generates a single crest in a medium.

____ 17. The principle of superposition relates the three wave quantities of speed, wavelength, and frequency.

____ 18. The nodal point of a standing wave forms due to the continuous destructive interference of two waves at that point.

____ 19. A suspended pendulum can be forced to move if an identical pendulum is suspended from the same support due to the effect of sympathetic vibrations.

____ 20. Large buildings, bridges, and other structures can be destroyed by low-speed winds, sometimes as low as 40 km/h, if they are not properly designed.

____ 21. The nodal lines in a two-point source interference pattern are parabolic in shape.

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.

____ 22. The period of a pendulum depends on which of the following?

 a. amplitude of the vibration d. density of the bob b. mass of the bob e. all of the above c. length of the pendulum

____ 23. The speed of any mechanical wave as it propagates through a medium is dependent mainly on the

 a. frequency of the wave source b. wavelength c. period of the wave d. type of medium through which the wave travels e. amplitude

____ 24. The shortest time interval in which a wave motion completely repeats itself (i.e., makes one complete vibration or oscillation) is called the

 a. amplitude d. frequency b. period e. speed c. wavelength

____ 25. A transverse wave has an amplitude of 2.4 m. What is the vertical distance, in metres, between the top of a crest and the bottom of a trough?

 a. 0.60 d. 3.6 b. 1.2 e. 4.8 c. 2.4

____ 26. A bob on a vertical spring bounces up and down to produce a longitudinal wave in the spring. If the distance in height between the bob's highest and lowest position is 12 cm, what is the amplitude of the generated wave?

 a. 3.0 cm d. 24 cm b. 6.0 cm e. 48 cm c. 12 cm

____ 27. An object completes 240 cycles in 15 s. What is its frequency, in hertz?

 a. 16 Hz d. 15 Hz b. 0.063 Hz e. 3600 Hz c. 240 Hz

____ 28. A pendulum completes 75 swings in 25 s. What is its period?

 a. 3.0 s d. 0.33 Hz b. 3.0 Hz e. none of the above c. 0.33 s

____ 29. The amplitude of the pendulum shown is approximately

 a. 18 mm d. 50 mm b. 25 mm e. 72 mm c. 36 mm

____ 30. Which point, shown in the diagram below, is in phase with point C?

 a. B d. F b. D e. G c. E

____ 31. In a transverse wave,

 a. The particles move parallel to the direction of the wave motion. b. The particles move perpendicular to the direction of the wave motion. c. Energy causes the particles to move forward with the wave. d. Energy is propagated by compressions and rarefactions. e. The speed is unaffected by the type of medium used.

____ 32. In a longitudinal wave,

 a. The particles move parallel to the direction of the wave motion. b. The particles move perpendicular to the direction of the wave motion. c. Energy causes the particles to move forward with the wave. d. Energy is propagated by crests and troughs. e. The speed is unaffected by the type of medium used.

____ 33. In an ideal wave, which of the following wave properties does not change as it travels along the same medium?

 a. amplitude d. period b. wavelength e. all of the above c. frequency

____ 34. The three possible types of vibrations are

 a. lateral, perpendicular, and parallel b. longitudinal, perpendicular, and parallel c. transverse, longitudinal, and torsional d. transverse, longitudinal, and lateral e. transverse, longitudinal, and circular

____ 35. In a crest, the particles

 a. are displaced at right angles to the rest position in a positive direction b. are displaced at right angles to the rest position in a negative direction c. move forward parallel to the direction of energy motion d. move backward parallel to the direction of energy motion e. remain at rest due to destructive interference

____ 36. A positive pulse is sent along a spring. A short time later, a negative pulse with a smaller amplitude returns. Assuming there are no frictional losses, which of the following statements could account for this observation?

 a. The other end of the spring is unattached (i.e., it is a free-end). b. The other end of the spring is attached to a fixed-end. c. The spring is attached to a second spring of higher density and slower speed. d. The spring is attached to a second spring of lower density and faster speed. e. There is not enough information to answer the question.

____ 37. As a wave travels down a spring, the amplitude slowly decreases. Why does this occur?

 a. The law of conservation of energy does not apply to waves. b. The energy is spread out along the entire length of the spring. c. The wave slows down as it travels along the spring. d. Some energy is lost due to friction as the particles in the spring rub against each other. e. all of the above

____ 38. Consider the following wave properties:

 (i) speed (ii) frequency (iii) wavelength (iv) period

Which of the above quantities does not change as a wave changes mediums?

 a. (i) only d. (i) and (iv) only b. (ii) only e. (ii) and (iv) only c. (i) and (iii) only

____ 39. A water wave travels from shallow water to deep water and speeds up. Which of the following statements best describes the wave's behaviour as it changes mediums?

 a. The wavelength is shorter in the shallow water and longer in the deeper water. b. The wavelength is longer in the shallow water and shorter in the deeper water. c. The wavelength is unaffected. d. The frequency of the wave is lower in the shallow water and higher in the deeper water. e. The frequency of the wave is higher in the shallow water and lower in the deeper water.

____ 40. The universal wave equation, , applies to which of the following wave types?

 a. water d. light b. sound e. all of the above c. radio waves

____ 41. The wavelength cannot be measured or calculated using

 a. speed divided by frequency d. twice the length of one crest b. frequency times period e. speed times period c. the total length of one crest and trough

____ 42. The speed of a wave can be measured in

 a. centimeters d. cycles per second b. meters e. hertz per second c. centimeters per second

____ 43. A sound wave with a frequency of 256 Hz, travelling at 340 m/s has a wavelength of

 a. 1.33 cm d. 1.33 m b. 0.75 m e. 87 km c. 0.75 cm

____ 44. Red light has a frequency of 4.0 ´ 1014 Hz and a speed of 3.0 ´ 108 m/s. What is its wavelength?

 a. 750 cm d. 750 ´ 10–7 m b. 750 nm e. 12 m c. 1.3 ´ 106 m

____ 45. An earthquake creates a seismic wave that travels at 3500 m/s with a wavelength of 1750 m. Find the frequency of the seismic wave.

 a. 2.0 m d. 0.50 Hz b. 0.50 m e. 2.0 Hz c. 2.0 kHz

____ 46. A guitar string produces a musical note with a wavelength of 75 cm. If the speed of sound in air is 344 m/s, what is the frequency of the note?

 a. 460 Hz d. 4.6 Hz b. 0.22 Hz e. 26 kHz c. 22 Hz

____ 47. A 512-Hz tuning fork produces a sound wave with a wavelength of 68 cm. With what speed does the sound wave travel?

 a. 34 km/h d. 750 m/s b. 7.5 m/s e. 13 m/s c. 350 m/s

____ 48. Which of the following statements is NOT true?

 a. Pulses reflected from a fixed-end are inverted. b. Pulses reflected from a free-end are not inverted. c. When a pulse enters a new medium no inversion occurs. d. When a wave changes mediums, partial reflection occurs. e. The phase of a transmitted wave depends on the change in speed of the wave.

____ 49. Which statement best describes the diagram below:

 a. The second medium is the faster medium. b. The second medium is the slower medium. c. The speeds are the same in each medium. d. The frequency in the second medium is higher. e. none of the above

____ 50. Which statement best describes what will occur at the barrier between the fast and slow medium, shown below?

 a. The reflected pulse will be in phase and the transmitted pulse will be inverted. b. The reflected pulse will be inverted and the transmitted pulse will be in phase. c. Both the reflected and transmitted pulses will be in phase. d. Both the reflected and transmitted pulses will be inverted. e. All of the wave energy will be reflected and inverted, and there will be no transmission.

____ 51. When you look very closely at a clear pane of glass, you can see a faint reflection of yourself even though the pane is transparent. Why does this occur?

 a. There are impurities in the glass that act as mirrors. b. It is an optical illusion created by the glass. c. Some of the light waves are partially reflected when they strike the glass surface. d. It results from the diffraction of light through the atomic spaces of the glass molecules. e. This phenomenon cannot yet be explained.

____ 52. The angle of incidence for a wave

 a. can be measured between the incident ray and the normal b. can be measured between the incident wavefront and the boundary c. is equal to the angle of reflection d. does not depend on the frequency of the source e. all of the above

____ 53. Waves can bend as they travel through small openings or past corners. This is due to the property called

 a. diffraction d. resonance b. refraction e. interference c. reflection

____ 54. Which of the following describes a wave's behaviour due to diffraction?

 a. The amount of diffraction is independent of wavelength. b. Faster waves diffract more than slower waves. c. Larger openings cause more diffraction to occur. d. Shorter wavelengths diffract less than longer wavelengths. e. Higher frequencies diffract more than lower frequencies if their speeds are the same.

____ 55. Waves can bend as they change speeds when travelling through different mediums. This is due to a property called

 a. diffraction d. resonance b. refraction e. interference c. reflection

____ 56. Which of the following describes a wave's behaviour due to refraction?

 a. The amount of refraction is independent of wavelength. b. Faster waves refract more than slower waves. c. Shorter wavelengths refract more than longer wavelengths. d. All waves of the same speed refract the same amount. e. Higher frequencies refract less than lower frequencies if their speeds are the same.

____ 57. During complete destructive interference, which of the following could be produced?

 a. supercrest d. antinode b. supernode e. resonance c. node

____ 58. What will occur when the two pulses, shown below, interfere with each other?

 a. A node is created, then the pulses will continue to travel on unaffected. b. A super crest is created, then the pulses will continue to travel on unaffected. c. A node is created, then the pulses bounce off each other and return to their starting points. d. The two pulses completely destroy each other and they disappear. e. The two pulses join to form a new crest and travel to the left together.

____ 59. An acoustic guitar contains a sound box that increases the loudness of the sounds the strings make. This is due to the property called

 a. amplification d. resonance b. refraction e. interference c. reflection

____ 60. Which of the following situations is a result of resonance?

 a. Hydro wires "hum" as a mild breeze blows over them. b. A child pushes herself on a swing by moving her legs back and forth appropriately. c. Windows in your house rattle as a large truck drives by. d. Buildings begin to sway when an earthquake occurs. e. all of the above

____ 61. A standing wave with three loops is generated in a string. If the wavelength is 10 cm, how far apart are the nodes created?

 a. 2.5 cm d. 20 cm b. 5.0 cm e. 30 cm c. 10 cm

____ 62. A three-loop standing wave is generated in a string by attaching one end to a wall and letting the transmitted and reflected waves interfere. If the wavelength of the wave is 15 cm, how far from the wall is the first antinode created?

 a. 3.75 cm d. 30 cm b. 7.5 cm e. 45 cm c. 15 cm

____ 63. What is the wavelength of the standing wave shown below?

 a. 16 m d. 2.0 m b. 8.0 m e. 1.0 m c. 4.0 m

____ 64. Which of the following statements concerning two-point source interference patterns created by identical sources in phase is NOT true?

 a. The nodal lines formed create symmetrical patterns. b. The nodal lines are hyperbolic. c. When the wavelength is increased, the nodal lines move closer together. d. When the frequency is increased, the nodal lines move closer together. e. The nodal lines represent areas of continual destructive interference.

____ 65. What conditions are needed to create a stationary two-point source interference pattern?

 a. The sources need only to have the same frequency. b. The sources need only to have the same frequency and wavelength. c. The sources need only to be in phase. d. The sources must have the same wavelength and be in phase. e. The sources can have any frequency and phase.

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