Discussed In Chapter 1:The Speed Of A Sound Wave In Air Depends Upon

Q1) The speed of a sound wave in air depends upon

1) its frequency 2) its wavelength 3) the air temperature 4) all of these 5) none of these

Q2) The speed of a sound wave is determined by:

1) its amplitude 2) its intensity 3) its pitch 4) number of harmonics present 5) the transmitting medium

Q3) Which sounds travel the fastest through air?

1) Higher pitch 2) Lower pitch 3) Louder sounds 4) Quieter sounds 5) They all travel at the same speed Q4) Sound travels faster in

1) air. 2) water. 3) steel. 4) a vacuum. 5) Sound travels at about the same speed in all of the above media.

Q5) The speed of a sound wave in air depends on

1) its frequency. 2) its wavelength. 3) the air temperature. 4) All of the above choices are correct. 5) None of the above choices are correct.

Q6) The approximate range of human hearing is

1) 10 hertz to 10,000 hertz. 2) 20 hertz to 20,000 hertz. 3) 40 hertz to 40,000 hertz. 4) Actually all of these it depends on the hearing ability of the person. Q7) Sound waves can interfere with one another so that no sound results.

1) True 2) False 3) Either true or false, depending on the air temperature.

Q7) A guitar string is plucked and set into vibration. The vibrating string disturbs the surrounding air, resulting in a sound wave. Which entry in the table below is correct?

wave in string sound wave 1) The wave is transverse. yes yes 2) The wave speed increases if temp. rises no yes 3) The wave is longitudinal. yes yes 4) The wave transports energy. yes no 5) none of the above

Q8) In the figure below, two point sources S1 and S2, which are in phase, emit identical sound waves of wavelength 2.0 m. If L1 = 39 m and L2 = 36 m, what type of interference occurs at point P?

1) fully constructive 2) fully destructive Q9) Two small identical speakers are connected (in phase) to the same source. The speakers are 3m apart and at ear level. An observer stands at X, 4m in front of one speaker as shown. If the amplitudes are not changed, the sound he hears will be least intense if the wavelength is:

1) 1 m 2) 2 m 3) 3 m 4) 4 m 5) 5 m

Q10) The intensity of a spherical wave 4.0 m from the source is 120 W/m2. What is the intensity at a point 9.0 m away from the source?

1) 11 W/m2 2) 24 W/m2 3) 53 W/m2 4) 80 W/m2 5) 270 W/m2 Q11) The standard reference sound level is about:

1) the threshold of human hearing at 1000 Hz 2) the threshold of pain for human hearing at 1000Hz 3) the level of sound produced when the 1 kg standard mass is dropped 1m onto a concrete floor 4) the level of normal conversation 5) the level of sound emitted by a standard 60Hz tuning fork

Q12) The intensity of sound wave A is 100 times that of sound wave B. Relative to wave B the sound level of wave A is:

1) -2db 2) +2 db 3) +10 db 4) +20 db 5) +100 db Q13) If the speed of sound is 340 m/s, the length of the shortest closed pipe (at one end) that resonates at 218Hz is: 1) 23 cm 2) 17 cm 3) 39 cm 4) 78 cm 5) 156 cm

Q14) Organ pipe Y (open at both ends) is half as long as organ pipe X (open at one end) as shown. The ratio of their fundamental frequencies fX:fY is:

1) 1:1 2) 1:2 3) 2:1 4) 1:4 5) 4:1

Q15) Two pipes are each open at one end and closed at the other. Pipe A has length L and pipe B has length 2L. Which harmonic of pipe B matches in frequency the fundamental of pipe A?

1) The fundamental 2) The second 3) The third 4) The fourth 5) There are none Q16) Five organ pipes are described below. Which one has the highest frequency fundamental?

1) A 2.3-m pipe with one end open and the other closed 2) A 3.3-m pipe with one end open and the other closed 3) A 1.6-m pipe with both ends open 4) A 3.0-m pipe with both ends open 5) A pipe in which the displacement nodes are 5m apart

Q17) A violin string, fixed at each end, has a length of 65 cm. Which pipe will support standing waves with the same frequencies as the violin string?

1) an open pipe of length 65 cm

2) a closed pipe of length 65 cm 3) an open pipe of length 130 cm 4) a closed pipe of length 130 cm 5) none of the above

Q18) Which one of the following superpositions will result in beats?

1) the superposition of waves that travel with different speeds 2) the superposition of identical waves that travel in the same direction 3) the superposition of identical waves that travel in opposite directions 4) the superposition of waves that are identical except for slightly different amplitudes. 5) the superposition of waves that are identical except for slightly different frequencies. Q19) Two timpani (tunable drums) are played at the same time. One is correctly tuned so that when it is struck, sound is produced that has a wavelength of 2.20 m. The second produces sound with a wavelength of 2.08 m. If the speed of sound is 343 m/s, what beat frequency is heard?

1) 7 beats/s 2) 9 beats/s 3) 11 beats/s 4) 13 beats/s 5) 15 beats/s

Q20) Beats are produced when two tuning forks, one of frequency 240 hertz and another of frequency 246 hertz are sounded together. The frequency of the beats is

1) 3 hertz 2) 6 hertz 3) 12 hertz 4) 240 hertz 5) 246 hertz

Q21) A 1056-hertz tuning fork is sounded at the same time a piano note is struck. You hear three beats per second. What is the frequency of the piano string?

1) 1053 hertz 2) 1056 hertz 3) 1059 hertz 4) 2112 hertz 5) not enough information given Q22) When a tuning fork is sounded together with a 492 Hz tone, a beat frequency of 2 Hz is heard. Then a small piece of putty is struck to the tuning fork, and the tuning fork is again sounded along with the 492 Hz tone. The beat frequency decreases. What is the frequency of the tuning fork?

1) 490 Hz 2) 492 Hz 3) 494 Hz 4) none of the above

Q23) Two identical tuning forks vibrate at 256Hz. One of them is then loaded with a drop of wax, after which 6 beats/s are heard. The period of the loaded tuning fork is:

1) 0.006 s 2) 0.005 s 3) 0.004 s 4) 0.003 s 5) none of these

Q24) The Doppler effect is characteristic of

1) water waves. 2) sound waves. 3) light waves. 4) all of the above choices 5) none of the above choices Q25) The Doppler effect also occurs when the source of sound is stationary and the listener is in motion. In which direction should the listener move to hear a higher frequency?

1) toward the sound source 2) away from the sound source

Q26) For light, a red shift indicates that the light source is moving

1) toward you. 2) away from you. 3) at right angles to you. 4) actually, all of these 5) none of these

Q27) When a car is at rest, its horn emits a sound wave of wavelength 0.55 m. A person standing in the middle of the street hears the horn with a frequency of 580 Hz. If the speed of sound is 330 m/s, should the person jump out of the way?

1) yes 2) no Q28) A stationary source S generates circular outgoing waves on a lake. The wave speed is 5.0 m/s and the crest-to- crest distance is 2.0 m. A person in a motorboat heads directly toward S at 3.0 m/s. To this person, the frequency of these waves is:

1) 1.0Hz 2) 1.5Hz 3) 2.0Hz 4) 4.0Hz 5) 8.0Hz

Q29) The diagram shows four situations in which a source of sound S with variable frequency and a detector D are either moving or stationary. The arrows indicate the directions of motion. The speeds are all the same. Detector 3 is stationary. The frequency detected is the same. Rank the situations according to the frequency of the source, lowest to highest.

1) 1, 2, 3, 4 2) 4, 3, 2, 1 3) 1, 3, 4, 2 4) 2, 1, 2, 3 5) None of the above