True/False Indicate whether the sentence or statement is true or false. ____

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

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

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

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

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

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

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

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

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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 b. 25 mm c. 36 mm

d. 50 mm e. 72 mm

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

____ 31.

____ 32.

____ 33.

____ 34.

____ 35.

____ 36.

____ 37.

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

____ 39.

____ 40.

____ 41.

____ 42.

____ 43.

____ 44.

____ 45.

____ 46.

____ 47.

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 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. 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 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 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 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 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 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 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 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?

____ 51.

____ 52.

____ 53.

____ 54.

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. 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. 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 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 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.

____ 55.

____ 56.

____ 57.

____ 58.

____ 59.

____ 60.

____ 61.

____ 62.

e. Higher frequencies diffract more than lower frequencies if their speeds are the same. 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 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. During complete destructive interference, which of the following could be produced? a. supercrest d. antinode b. supernode e. resonance c. node 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. 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 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 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 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. Completion Complete each sentence or statement. 66. _________________________ occurs when a vibration or oscillation is repeated in equal intervals of time. 67. The number of cycles, oscillations, or vibrations an object makes in one second is called the object's ____________________. 68. The ____________________ of a vibration is the amount of time taken to make one complete oscillation. 69. A(n) ____________________ is the part of a longitudinal wave in which the particles are closer together than when they are at rest. 70. When two students send opposite pulses towards each other on a rope, the point on the rope where the two pulses meet experiences ____________________ interference. 71. A(n) _________________________ can be created when two students, standing at opposite ends of a rope, generate waves of equal frequency and amplitude. 72. The ____________________ of a transverse wave can be measured as the distance from crest to crest or as the distance from trough to trough. 73. The ____________________ of a wave is measured from the medium's rest position to its maximum displacement on either side. 74. A(n) ____________________ can transfer energy between two points as a disturbance without the particles of the medium propagating forward with the energy. 75. The ____________________ indicates the direction of energy transmission in a disturbance. 76. In a(n) ____________________ wave, the particles of the medium vibrate parallel to the direction of energy propagation. 77. A parabolic reflector causes straight waves to reflect to a specific place called the ____________________. 78. Pushing children on a swing at the correct times to make them move properly uses the property of _________________________.

Matching Match the following words to the most appropriate statement below. Note that not all words will be matched. a. cycle h. transverse vibration b. antinodal point i. diffraction c. refraction j. fixed-end reflection d. longitudinal vibration k. supercrest e. crest l. free-end reflection f. rarefaction m. torsional vibration g. nodal point ____ ____ ____ ____ ____ ____ ____ ____

79. 80. 81. 82. 83. 84. 85. 86.

occurs when an object vibrates perpendicularly to its axis point of destructive interference that remains at rest region in a longitudinal wave where particles are farther apart than normal bending of a wave due to changing speeds (or mediums) occurs when an object twists around its axis reflection from a rigid end in which the pulse is inverted one complete vibration, oscillation, or back and forth motion interference that results when crest meets crest

Short Answer 87. Often, when you look very closely at a clear pane of glass, you can see a faint reflection of yourself even though the glass is transparent. Explain why this occurs. 88. A grandfather clock is running slow. What could be done to correct this? 89. State the type of vibration that occurs in each of the following: (a) the spring in a pogo stick as a child bounces up and down on it (b) a tree swaying in the wind (c) the rotating masses on an anniversary clock 90. When playing a stereo, there are certain sounds that can cause windows to rattle. Explain why this occurs. 91. Buildings that are constructed in areas prone to earthquakes must have energy absorption features built into their design. Explain why this is done. 92. For each of the following, calculate the frequency, in hertz, and the period, in seconds: (a) a bee beating its wings 3000 times in 30 s (b) a tuning fork completing 2048 oscillations in 8.0 s 93. For each of the following, calculate the frequency, in hertz, and the period, in seconds: (a) a pendulum swinging 20 times per minute (b) a car engine rotating at 8000 rpm's (revolutions per minute) 94. For the wave shown below, measure the wavelength and amplitude using a ruler.

95. You are holding a rope in your hand that is unattached at the other end. You move your hand quickly sideways and cause the far end of the rope to knock a can off a post. How was the energy transmitted to the can to knock it off the post?

96. Give some examples of transverse vibrations. 97. What effect does increasing each of the following have on the wavelength of a wave? (a) amplitude, if speed is constant (b) speed, if frequency is constant (c) frequency, if speed is constant 98. A water wave travels from shallow water (slower medium) into deeper water (faster medium). What happens to the wavelength and frequency of the water wave? 99. Complete the table below. Incident Pulse

Reflected Pulse

Transmitted Pulse

negative

negative

positive

Medium Change

slow to fast positive

fast to slow

100. Three ropes (X, Y, and Z) made of different materials are attached in a linear fashion. Based on the following observations, classify ropes X, Y, and Z as fast, intermediate, or slow media. -A negative pulse transmitted into X is inverted upon reflection and is transmitted into Y as negative. -A negative pulse in Y is inverted upon reflection and is transmitted into Z as negative. 101. Straight waves travel towards a parabolic barrier. Describe the reflected waves. 102. Describe two ways in which the amount of diffraction occurring in a wave can be increased. 103. Sketch the resultant wave form when the following two pulses meet. (Assume the meeting point corresponds to the centre of each pulse.)

104. Describe how the principle of superposition can be used to find the resultant wave form when two or more waves interfere. 105. Describe how you could use the principle of resonance to remove a metal stake that is buried deeply into the ground. 106. Which wave property allows the formation of standing waves to occur? Explain your answer. 107. Draw a scale diagram of a standing wave with five nodes, created using a rope that is 25 m long and is fixed at both ends. What is the wavelength of the wave? 108. You are standing in a room that has two speakers, one placed at each corner at the front of the room. The speakers are connected to the same source and are emitting a pure 500-Hz signal. As you walk across the back of the room, you notice the sound from the speakers varies in intensity from louder to quieter. Explain this observation. Problem 109. The amplitude of vibration of a monarch butterfly's wings is 1.5 cm. If the frequency of vibration of the wings is 9.0 Hz, through what distance, in metres, do the wing tips travel in 1.0 min? 110. Calculate the period and frequency of a pendulum that completes 150 vibrations in 1.5 min.

111. The distance between two successive crests in a wave is 1.5 m, and the source generates 25 crests and 25 troughs in 5.0 s. What is the speed of the waves? 112. The distance between the second and sixth crests in a wave is 75 cm, and one crest travels a distance of 25 cm in 3.0 s. Find the frequency of the wave. 113. A sound wave with a frequency of 1.25 × 104 Hz travels at 344 m/s. What is its wavelength? 114. A wave on a coiled spring travels at 6.2 m/s with successive crests separated by a distance of 1.25 m. What is the period of the waves? 115. A standing wave is generated in a string so that 3 loops are present. The length of the string is 15 m and the frequency of the source is 2.5 Hz. (a) Find the wavelength of the waves. (b) Find is the speed of the waves in the string. 116. A standing wave is created in a string of length 12.5 m. If the waves travel at 5.0 m/s with a frequency of 2.0 Hz, how many loops are present in the string? 117. The distance between the first and fourth nodes in a standing wave is 30.0 cm. If the waves travel at 2.50 m/s, what is the frequency of the waves? 118. A standing wave with five loops is generated in a string. If the waves travel at 17.5 m/s with a frequency of 1.40 × 102 Hz, how long is the string? 119. Standing waves are produced in a string that is 4.0 m long. If the waves are travelling at 125 cm/s and the distance between the first and fifth nodes is 80.0 cm, find the wavelength and frequency of the waves. Essay 120. Discuss, in detail, the motion of mechanical waves with regard to the following properties: transmission, reflection, refraction, diffraction, and interference.

Answer Section TRUE/FALSE 1. T 12. F

2. F 13.T

3. T 14. T

4. F 15. F

5. F 16. F

6. T 17. F

7. T 18. T

8. F 19. T

9. T 20. T

10. T 11. F 21. F

MULTIPLE CHOICE 22. 30. 38. 46. 54. 62.

C E E A D A

23. D 31. B 39. A 47. C 55. B 63. C

24. B 32. A 40. E 48. E 56. C 64. C

25. E 33. E 41. B 49. A 57. C 65. D

26. B 34. C 42. C 50. B 58. A

27. A 35. A 43. D 51. C 59. D

28. C 36. C 44. B 52. E 60. E

COMPLETION 66. Periodic motion 67. frequency 70. destructive 71. standing wave 74. wave 75. wave ray 78. resonance mechanical resonance

68. period 72. wavelength 76. longitudinal

69. compression 73. amplitude 77. focal point

29. A 37. D 45. E 53. A 61. B

MATCHING 79. H

`

80. G

81. F

82. C

83. M

84. J

85. A

86. K

SHORT ANSWER 87. As the light waves strike the glass surface, their speed changes since there is a change in medium. This causes partial reflection of the light waves from the surface of the glass. It is this partial reflection that you can see. Since very little of the light is reflected, the image seen is very faint. 88. Since the clock is running slow, its frequency is too low, making its period too long. Since the period of a pendulum is related to length, decreasing the length of the pendulum will decrease the period as well. This will increase the frequency of the clock, making it run faster. 89. (a) longitudinal (b) transverse (c) torsional 90. The stereo is creating sound waves that have the same natural frequency as the windows in the car. This causes sympathetic vibrations to start in the windows and makes them rattle. This effect is due to resonance. 91. Buildings, typically those between 5 and 40 storeys tall, are resonant at earthquake frequencies. This would cause the buildings to start swaying when earthquakes occur. The energy absorption features built into the frame of the building absorbs the energy of the waves and prevents the buildings from swaying. 92. (a) frequency = 100 Hz, period = 0.010 s (b) frequency = 256 Hz, period = 0.0039 s 93. (a) frequency = 0.33 Hz, period = 3.0 s (b) frequency = 133 Hz, period = 0.0075 s 94. wavelength = 2.0 cm amplitude = 1.0 cm 95. By quickly moving your hand sideways, you generated a wave pulse in the rope. The energy from the motion of your hand was transmitted along the rope in the transverse pulse that you created. Eventually, it reached the other end of the rope and transmitted the energy to the can, knocking it off the post. 96. Answers will vary but could include: -a tree swaying in the wind -a string being plucked/played -water waves (although they are not completely transverse) -a skipping rope -a swinging pendulum -a woodpecker pecking on a tree 97. (a) no effect (b) increase in wavelength (c) decrease in wavelength 98. The wavelength increases (according to the wave equation, v α λ). The frequency is unchanged, as frequency is determined only by the source. 99. Incident Pulse

Reflected Pulse

Transmitted Pulse

Medium Change

negative

negative

negative

slow to fast

positive

positive

positive

slow to fast

positive

negative

positive

fast to slow

100. X: fast (reflected pulse is inverted, therefore next medium is slower) Y: intermediate (reflected pulse is inverted, therefore next medium is slower) Z: slow 101. The reflected waves are circular and appear to meet at a single point called the focal point. This can be predicted using the laws of reflection and ray diagrams. 102. Diffraction can be increased by increasing the wavelength or decreasing the size of the opening. 103. Use the principle of superposition.

104. The resultant displacement of the final wave form can be determined by simply adding the individual displacements for each wave at that point. This can be done manually by choosing several key reference points and drawing the resultant wave form, or electronically by feeding the data into a processor and having the result displayed on a monitor (oscilloscope, computer screen, etc.). 105. By rocking the metal stake back and forth at the proper frequency and beginning with small amplitudes, the stake will begin to vibrate. Although the initial vibrations will be quite small, they will slowly start to increase in amplitude. Repeatedly applying the force at the proper time will cause the vibrations to eventually become large enough to move enough soil out of the way and allow the stake to be pulled easily out of the ground. 106. The wave property of interference allows standing waves patterns to form. Constructive interference allows the standing wave to form antinodes (or loops), while destructive interference allows the standing wave to form nodes. The interfering waves must have identical frequencies and wavelengths in order to produce standing waves. 107.

The wavelength of the wave is 12.5 m.

108. You are experiencing a two-point source interference pattern between the two speakers. Since the speakers are identical sources, there is a symmetrical pattern of alternating areas of constructive interference (louder areas) and destructive interference (quieter areas) radiating outward from the speakers as the sound signals from each speaker interfere with one another. As you walk across the back of the room, you are walking across this pattern. PROBLEM 109. 110. 111. 112. 113. 114. 115. 116. 117. 118. 119.

The wing tips move through a distance of 32 m. The period is 0.60 s and the frequency is 1.7 Hz. The speed of the waves is 7.5 m/s. The frequency of the wave is 0.44 Hz. The wavelength is 2.75 × 10–2 m. The period is 0.20 s. (a) The wavelength is 10 m. (b) The speed of the waves is 25 m/s. There are 10 loops present in the string. The frequency is 12.5 Hz. The string is 0.313 m long. The wavelength is 40.0 cm. The frequency is 3.12 Hz.

ESSAY 120. Transmission -Mechanical waves need a medium in which to travel. -The frequency is determined by the source alone. -The speed of a wave depends on the medium through which it travels.

-The universal wave equation

relates speed, frequency, and wavelength.

Reflection -All waves obey the laws of reflection (angle of incidence equals angle of reflection). Refraction -The bending of a wave as it changes mediums/speeds. -When a wave strikes a boundary at an oblique angle, its direction changes. -When a wave strikes a boundary straight on, no refraction occurs. -The amount of refraction depends on the wavelength. (Longer wavelengths bend less than shorter wavelengths.) Diffraction -The bending of a wave around corners or through openings. -The amount of diffraction depends on wavelength and opening size. (Longer wavelengths diffract more; small openings cause more diffraction.)