Chapter 10 Waves and Sound
10.1 Vibrations and Waves
1) A wiggle in time is a
A) vibration.
B) wave.
C) both
D) neither
Answer: A
2) A wave is a vibration in
A) space.
B) time.
C) both
D) neither
Answer: C
3) When we consider how frequently a pendulum swings to and fro we're talking about its
A) frequency.
B) period.
C) wavelength.
D) amplitude.
Answer: A
4) When we consider the time taken for a pendulum to swing to and fro we're talking about the
pendulum's
A) frequency.
B) period.
C) wavelength.
D) amplitude.
Answer: B
5) When we consider the distance a pendulum swings to and fro we're talking about the
pendulum's
A) frequency.
B) period.
C) wavelength.
D) amplitude.
Answer: D
6) A wave having a frequency of 1000 Hz vibrates at
A) less than 1000 cycles per second.
B) 1000 cycles per second.
C) more than 1000 cycles per second.
Answer: B
7) How many vibrations per second are associated with a 101-MHz radio wave?
A) less than 101,000,000
B) 101,000,000
C) more than 101,000,00
Answer: B
8) If the frequency of a certain wave is 10 Hz, its period is
A) 0.1 s.
B) 10 s.
C) 100 s.
D) none of the above
Answer: A
9) A 60 vibration per second wave travels 30 m in 1 s. Its frequency is
A) 30 Hz and it travels at 60 m/s.
B) 60 Hz and it travels at 30 m/s.
C) neither
Answer: B
10) In Europe an electric razor completes 50 vibrations in 1 s. The frequency of these vibrations
is
A) 50 Hz with a period of 1/50 s.
B) 1/50 Hz with a period of 50 s.
C) 50 Hz with a period of 50 s.
D) 1/50 Hz with a period of 1/50 s.
Answer: A
11) A mass on the end of a spring bobs up and down 1 complete cycle every 2 s. Its frequency is
A) 0.5 Hz.
B) 2 Hz.
C) neither
Answer: A
12) The frequency of the second hand on a clock is
A) 1 Hz.
B) 1/60 Hz.
C) 60 Hz.
Answer: B
13) The period of the second hand on a clock is
A) 1 s.
B) 1/60 s.
C) 60 s.
D) 3600 s.
E) 12 h.
Answer: C
14) A weight suspended from a spring bobs up and down one complete cycle every 2 s. Its
frequency is
A) 0.5 Hz.
B) 1 Hz.
C) 2 Hz.
D) none of the above
Answer: A
15) A weight suspended from a spring bobs up and down one complete cycle every 2 s. Its
period is
A) 0.5 s.
B) 1 s.
C) 2 s.
D) none of the above
Answer: C
16) If you double the frequency of a vibrating object, its period
A) doubles.
B) is half.
C) is one quarter.
Answer: B
17) The pendulum with the greatest frequency has the
A) shortest period.
B) shortest length.
C) both
D) neither
Answer: C
18) When a pendulum clock at sea level is placed at the top of a high mountain, it will
A) gain time.
B) lose time.
C) neither
Answer: B
19) A child swings to and fro on a playground swing. If the child stands on the swing rather than
sitting on it, the time for a to-and-fro swing is
A) lengthened.
B) shortened.
C) unchanged.
Answer: B
20) What is the relationship between wave frequency and period? What is the period, in seconds,
that corresponds to each of the following frequencies: (a) 10 Hz, (b) 0.2 Hz, (c) 60 Hz?
Answer: Wave frequency and period are reciprocals of each other: That is, f = 1/T and T = 1/f.
So for the three given frequencies, T = 1/f = (a) 0.10 s, (b) 5 s, (c) 1/60 s.
10.2 Wave Motion
1) The source of all wave motion is a
A) wave pattern.
B) harmonic object.
C) vibrating object.
D) region of variable high and low pressure.
E) none of the above
Answer: C
2) What moves from place to place in wave motion is
A) energy.
B) momentum.
C) pressure.
D) matter.
Answer: A
3) The medium in which a wave travels
A) moves along with the wave.
B) transmits the wave.
C) inhibits the wave.
D) reflects the wave.
Answer: B
4) A wave travels an average distance of 6 m in 1 s. What is the wave's velocity?
A) less than 0.2 m/s
B) 1 m/s
C) 3 m/s
D) 6 m/s
E) more than 6 m/s
Answer: D
5) A wave oscillates up and down two complete cycles each 1 s. If the wave travels an average
distance of 6 m in 1 s, its wavelength is
A) 0.5 m.
B) 1 m.
C) 2 m.
D) 3 m.
E) 6 m.
Answer: D
6) A floating leaf oscillates up and down two complete cycles each 1 s as a water wave passes
by. What is the wave's frequency?
A) 0.5 Hz
B) 1 Hz
C) 2 Hz
D) 3 Hz
E) 6 Hz
Answer: C
7) A floating leaf oscillates up and down 2 complete cycles in 1 s as a water wave of wavelength
10 m passes by. What is the wave's speed?
A) 2 m/s
B) 10 m/s
C) 20 m/s
D) 40 m/s
E) more than 40 m/s
Answer: C
8) You dip your finger repeatedly into water and make waves. If you dip your finger more
frequently, the wavelength of the waves
A) shortens.
B) lengthens.
C) remains the same.
Answer: A
9) During a single period, the distance traveled by a wave is
A) one-half wavelength.
B) one wavelength.
C) two wavelengths.
Answer: B
10) Radio waves travel at the speed of light, 300,000 km/s. The wavelength of a radio wave
received at 100 MHz is
A) 0.3 m.
B) 3.0 m.
C) 30 m.
D) 300 m.
E) none of the above
Answer: B
11) As a train of water waves goes by, a piece of cork floating on the water bobs up and down
one complete cycle each second. The waves are 2 m long. What is the speed of the wave?
A) 0.25 m/s
B) 0.50 m/s
C) 1.0 m/s
D) 2 m/s
E) 4 m/s
Answer: D
12) A skipper on a boat notices wave crests passing the anchor chain every 5 s. The skipper
estimates the distance between crests is 15 m. What is the speed of the water waves?
A) 3 m/s
B) 5 m/s
C) 15 m/s
D) not enough information
Answer: A
13) A boat at anchor is rocked by waves whose crests are 40 m apart and with wave speed 10
m/s. These waves reach the boat once every
A) 400 s.
B) 30 s.
C) 4.0 s.
D) 0.25 s.
Answer: C
14) A wave travels an average distance of 1 m in 1 s with a frequency of 1 Hz. Its amplitude is
A) less than 1 m.
B) 1 m.
C) more than 1 m.
D) not enough information
Answer: D
15) Show the relationship between wave speed and wave frequency. If the speed of a
longitudinal wave is 340 m/s and the frequency is 1000 Hz, what is the wavelength of the wave?
Answer: Speed = wave frequency × wavelength. So wavelength = speed/frequency = (340
m/s)/(1000 Hz) = 0.34 m.
10.3 Transverse and Longitudinal Waves
1) In a longitudinal wave, the compressions and rarefactions travel in
A) the same direction.
B) opposite directions.
C) neither
Answer: A
2) Which of the following is not a transverse wave?
A) sound
B) light
C) radio
D) all of the above
E) none of the above
Answer: A
3) Which of the following is a longitudinal wave?
A) sound
B) light
C) radio
D) all of the above
E) none of the above
Answer: A
4) The vibrations of a transverse wave move in a direction
A) along the direction of wave travel.
B) at right angles to the direction of wave travel.
C) opposite to wave travel.
Answer: B
5) The vibrations of a longitudinal wave move in a direction
A) along the direction of wave travel.
B) at right angles to the direction of wave travel.
C) opposite to wave travel.
Answer: A
6) A sound wave is a
A) longitudinal wave.
B) transverse wave.
C) standing wave.
D) shock wave.
E) none of the above
Answer: A
7) Compressions and rarefactions are characteristic of
A) longitudinal waves.
B) transverse waves.
C) both
D) neither
Answer: A
8) Compressions and rarefactions normally travel
A) at right angles to the wave.
B) in the same direction in a wave.
C) in opposite directions in a wave.
D) none of the above
Answer: B
9) A compression is a squash and a rarefaction is a
A) crunch.
B) reverse tension.
C) stretch.
Answer: C
10) Distinguish between a transverse wave and a longitudinal wave. Give examples of each.
Answer: All waves are vibrations in space and time. In a transverse wave, the vibrations are
perpendicular to the direction of wave travel. Vibrations in a longitudinal wave are along the
direction of wave travel. Transverse waves include those of a vibrating string and
electromagnetic waves. Examples of longitudinal waves are sound, those in a to-and-fro
vibrating slinky, and some types of earthquake waves.
10.4 Sound Waves
1) The source of all sounds is something that is
A) accelerating.
B) moving.
C) vibrating.
D) undergoing simple harmonic motion.
Answer: C
2) A sound source of high frequency emits a high
A) speed.
B) amplitude.
C) pitch.
D) all of the above
E) none of the above
Answer: C
3) Double the frequency of sound and you also double its
A) wavelength.
B) speed.
C) amplitude.
D) all of the above
E) none of the above
Answer: E
4) The range of human hearing is about
A) 10 Hz - 10,000 Hz.
B) 20 Hz - 20,000 Hz.
C) 40 Hz - 40,000 Hz.
D) all of the above, depending on the person
Answer: B
5) Our ears are best at hearing
A) infrasonic sound.
B) ultrasonic sound.
C) both
D) neither
Answer: D
6) Sound travels faster in
A) air.
B) water.
C) steel.
D) a vacuum.
E) same in each
Answer: C
7) Sound waves cannot travel in
A) air.
B) water.
C) steel.
D) a vacuum.
Answer: D
8) The speed of a sound wave in air depends on
A) its frequency.
B) its wavelength.
C) the air temperature.
D) all of the above
E) none of the above
Answer: C
9) Sound travels faster when the air is
A) warm.
B) cold.
C) neither
Answer: A
10) A 340-Hz sound wave travels at 340 m/s in air with a wavelength of
A) 1 m.
B) 10 m.
C) 100 m.
D) 1000 m.
E) none of the above
Answer: A
11) Sound travels fastest in
A) water vapor
B) water
C) ice
Answer: C
12) An explosion occurs 34 km away. For sound that travels at 340 m/s, you'll hear the explosion
in
A) 0.1 s.
B) 1 s.
C) 10 s.
D) 20 s.
E) more than 20 s.
Answer: E
13) A general rule for estimating the distance in kilometers between an observer and a lightning
bolt is to count the number of seconds between seeing the lightning and hearing it, and dividing
by
A) 2.
B) 3.
C) 4.
D) 5.
E) none of the above
Answer: B
14) What is an echo, and why is it weaker than the original sound?
Answer: An echo is reflected sound. Because sound from a small source spreads out via the
inverse square law, sound intensity per unit area decreases with distance to the reflecting surface,
and when reflected continues to decrease with distance. Hence, the echo you hear is weaker than
the original sound.
10.5 Reflection and Refraction of Sound
1) The reflection of sound is
A) reverberation.
B) an echo.
C) bouncing waves.
Answer: B
2) Sound energy that is not reflected is
A) transmitted.
B) absorbed.
C) either or both
Answer: C
3) Reverberation is a phenomenon you would likely to hear if you sing in the
A) shower.
B) desert.
C) tundra.
Answer: A
4) Reverberation is a case of
A) sound interference.
B) forced vibrations.
C) re-echoed sound.
D) resonance.
E) none of the above
Answer: C
5) The explanation for all types of refraction involves a change in
A) frequency.
B) period.
C) speed.
D) all of the above
E) none of the above
Answer: C
6) Refraction of sound can occur in
A) air.
B) water.
C) both
D) neither
Answer: C
7) When sound travels faster at ground level than higher in the air, sound tends to bend
A) upward.
B) downward.
C) neither
Answer: A
8) When sound travels faster higher above ground level than it does closer to the ground, sound
bends
A) upward.
B) downward.
C) neither
Answer: B
9) On days when the air nearest the ground is colder than air above, sound waves
A) tend to be refracted upward.
B) tend to be refracted downward.
C) travel without refraction.
Answer: B
10) Sound refraction depends on the speed of sound being
A) constant.
B) variable.
C) proportional to frequency.
D) inversely proportional to wavelength.
E) none of the above
Answer: B
11) A dolphin perceives its environment by the sense of
A) sight.
B) sound.
C) both
D) neither
Answer: C
12) In designing a music hall, an acoustical engineer is concerned with
A) modulation.
B) forced vibrations.
C) resonance.
D) beats.
E) wave interference.
Answer: E
13) While at a concert, a wind blows directly from the orchestra toward you. You hear the
average frequencies of sound
A) decreased.
B) increased.
C) neither
Answer: C
14) While at a concert, a wind blows directly from the orchestra toward you. The speed of the
sound you hear is
A) decreased.
B) increased.
C) neither.
Answer: B
15) While at a concert, a wind blows directly from the orchestra toward you. The wavelength of
the sound you hear is
A) decreased.
B) increased.
C) neither
Answer: B
16) A bat chirps to locate a tasty lunch. The chirp travels at 340 m/s and its echo is heard 1 s
after the chirp. Distance to the lunch is
A) 85 m.
B) 170 m.
C) 340 m.
Answer: C
17) Ultrasonic sound that travels at 1530 m/s in ocean water is bounced off the ocean floor and
returns to the ship above. If the round trip takes 3 s, the depth of the water is
A) 1530 m.
B) 2295 m.
C) 3060 m.
D) 4590 m.
Answer: B
10.6 Forced Vibrations and Resonance
1) The natural frequency of an object depends on its
A) elasticity.
B) size and shape.
C) both
D) neither
Answer: C
2) The object with the natural frequency of higher pitch is a
A) small bell.
B) large bell.
C) either
D) neither
Answer: A
3) The least amount of energy is required to produce forced vibration in an object
A) below its natural frequency.
B) at its natural frequency.
C) above its natural frequency.
Answer: B
4) Resonance occurs when a 200-Hz tuning fork encounters a sound wave with a frequency of
A) 150 Hz.
B) 200 Hz.
C) 300 Hz.
D) any of the above
E) none of the above
Answer: B
5) A bass fiddle is louder than a harp because of its
A) thicker strings.
B) sounding board.
C) lower pitch.
D) all of the above
E) none of the above
Answer: B
6) When the handle of a tuning fork is held solidly against a table, the sound becomes louder and
the time the fork keeps vibrating becomes
A) longer.
B) shorter.
C) remains the same
Answer: B
7) Some singers are able to shatter a crystal chandelier with their voice, which illustrates
A) an echo.
B) sound refraction.
C) beats.
D) resonance.
E) interference.
Answer: D
8) Resonance can be viewed as forced vibration with the
A) least amount of energy input.
B) maximum amount of energy input.
C) matching of wave amplitudes.
D) matching of constructive and destructive interference.
E) minimum beat frequency.
Answer: A
9) Troops break step when marching across a bridge to prevent
A) interference.
B) resonance.
C) wave motion.
D) frequency distortion.
Answer: B
10) What is resonance and the conditions for resonance? Give examples.
Answer: Resonance is an unusually large increase in amplitude when a system is driven at its
natural frequency by an external force. An example is someone pushing another person on a
swing. When the pushes are in rhythm with the natural swing motion, very soon the swing is
high in the air with little effort by the person doing the pushing. Other examples are the sounding
of a tuning fork by the vibrations of another nearby tuning fork of matched frequency and the
destruction of a bridge when small pushes, stepping or gusts of wind, are applied in rhythm with
the natural frequency of the bridge.
10.7 Interference
1) To say that one wave is out of phase with another is to say that the waves are
A) of different amplitudes.
B) of different frequencies.
C) of different wavelengths.
D) out of step.
E) all of the above
Answer: D
2) Wave interference occurs for
A) sound waves.
B) light waves.
C) water waves.
D) all of the above
E) none of the above
Answer: D
3) A standing wave occurs when
A) two waves overlap.
B) a wave reflects upon itself.
C) the speed of the wave is zero or near zero.
D) the amplitude of a wave exceeds its wavelength.
Answer: B
4) A node is a position of
A) minimum amplitude.
B) maximum amplitude.
C) neither
Answer: A
5) Sound waves can interfere with one another so that no sound is produced.
A) True
B) False
Answer: A
6) The phenomenon of beats results from sound
A) refraction.
B) reflection.
C) interference.
D) all of the above
E) none of the above
Answer: C
7) When you tune a radio to a certain station, you match the frequency of the internal electrical
circuit to the frequency of that radio station, which illustrates
A) forced vibrations.
B) resonance.
C) beats.
D) reverberation.
E) wave interference.
Answer: B
8) What beat frequency is produced when a 240-Hz and a 246-Hz tuning fork are sounded
together?
A) 6 Hz
B) 12 Hz
C) 240 Hz
D) 245 Hz
E) none of the above
Answer: A
9) A 1056-Hz tuning fork is sounded when a piano note is struck. You hear three beats per
second. What is the frequency of the piano string?
A) 1053 Hz
B) 1056 Hz
C) 1059 Hz
D) 2112 Hz
E) not enough information
Answer: E
10) Suppose you sound a 1056-Hz tuning fork when you strike a note on the piano and hear 2
beats/second. You tighten the piano string very slightly and now hear 3 beats/second. What is the
frequency of the piano string?
A) 1053 Hz
B) 1054 Hz
C) 1056 Hz
D) 1058 Hz
E) 1059 Hz
Answer: E
11) Two tuning forks produce sounds of wavelengths 3.4 m and 3.3 m. What beat frequency is
produced?
A) 0.1 Hz
B) 1.0 Hz
C) 2.0 Hz
D) 3.0 Hz
E) 4.0 Hz
Answer: D
12) What is wave interference, and the two types of wave interference?
Answer: Wave interference is the result of two or more waves combining together. When they
combine in phase-that is, with crests overlapping crests and troughs overlapping troughs-the
resulting wave has greater amplitude. This is constructive interference. When crests overlap
troughs, cancellation or diminishing of the wave results. This is destructive interference.
13) Why will a struck tuning fork sound louder when it is held against a table?
Answer: The sound is louder because the vibrating surface area is increased when the tuning fork
is held against the table. The tabletop with its large area is set into forced vibration.
14) What are beats and how are they produced?
Answer: Beats are the sequence of alternating reinforcement and cancellation of two sets of
superimposing waves differing in frequency, and heard as a throbbing sound. Beats have a
frequency of their own equal to the difference between the two wave frequencies. Beats are
evident when a pair of slightly mismatched tuning forks is sounded. They are also evident with a
pair of whining diesel engines run side by side.
10.8 Doppler Effect
1) The Doppler effect is characteristic of
A) water waves.
B) sound waves.
C) light waves.
D) all of the above
E) none of the above
Answer: D
2) A Doppler effect occurs when a source of sound moves
A) toward you.
B) away from you.
C) either
D) neither
Answer: C
3) A Doppler effect occurs when a source of sound moves
A) toward you.
B) at right angles to you.
C) both
D) neither
Answer: A
4) For light, a red shift indicates the light source moves
A) toward you.
B) away from you.
C) at right angles to you.
D) all of the above
E) none of the above
Answer: B
5) In perceiving its environment, a dolphin makes use of
A) echoes.
B) the Doppler effect.
C) ultrasound.
D) all of the above
E) none of the above
Answer: D
6) What is the Doppler effect, and how is it produced? Cite two examples.
Answer: The Doppler effect is change in frequency produced by relative motion between a
receiver and the source of a wave. If a wave source approaches a receiver, waves encounter the
receiver more often and a higher frequency is perceived. If a wave source recedes, waves
encounter a receiver less often and a lower frequency is perceived. In the case of sound, when a
siren from a fire engine or ambulance approaches you, its pitch is higher. And when the vehicle
passes, moving away, the pitch is lower. In the case of light, the spin of a star can be determined
by noting that one edge has a slightly different color than the opposite edge. The edge spinning
toward you will be slightly blue-shifted, while the edge spinning away from you has a slight red
tinge.
10.9 Bow Waves and the Sonic Boom
1) Which doesn't belong to the same family?
A) infrasonic waves
B) ultrasonic waves
C) radio waves
D) shock waves
E) longitudinal waves
Answer: C
2) A wave barrier is produced in water when the speed of an object
A) matches the speed of waves in water.
B) exceeds the speed of waves in water.
C) is less than the speed of waves in water.
D) none of the above
Answer: A
3) A bow wave is produced in water when the speed of an object
A) matches the speed of waves in water.
B) exceeds the speed of waves in water.
C) is less than the speed of waves in water.
D) none of the above
Answer: B
4) A shock wave is produced when the speed of an object
A) matches the speed of sound in air.
B) exceeds the speed of sound in air.
C) is less than the speed of sound in air.
D) none of the above
Answer: B
5) A sonic boom can NOT be produced by
A) an aircraft flying slower than the speed of sound.
B) a whip.
C) a speeding bullet.
D) all of the above
Answer: A
6) Why does a sonic boom irritate people on the ground below a supersonic aircraft and not
passengers inside the aircraft?
Answer: People below encounter the aircraft's shock wave, whereas passengers inside do not.
Consider the analogous case of a boat on a river. People on shore may be doused by the bow
wave as the boat passes, but passengers inside the boat don't encounter the bow wave at all. Or a
dolphin at a sea-world show may splash onlookers while not encountering the splash at all.
10.10 Musical Sounds
1) The pitch of a musical sound depends on the sound wave's
A) wavelength.
B) frequency.
C) speed.
D) amplitude.
E) all of the above
Answer: B
2) The loudness of a musical sound is a measure of the sound wave's
A) wavelength.
B) frequency.
C) speed.
D) amplitude.
E) all of the above
Answer: D
3) The quality of a musical note has to do with its
A) loudness.
B) frequency.
C) harmonics.
D) amplitude.
E) all of the above
Answer: C
4) High pitched sound has a high
A) speed.
B) frequency.
C) number of partial tones.
D) all of the above
E) none of the above
Answer: B
5) The fundamental frequency of a violin string is 440 Hz. The frequency of its second harmonic
is
A) 220 Hz.
B) 440 Hz.
C) 880 Hz.
Answer: C
6) The amplitude of a sound wave is closely related to
A) loudness.
B) pitch.
C) quality.
D) timbre.
E) all of the above
Answer: A
7) All other things being the same, strings having more mass than other strings will produce
A) higher frequency notes.
B) lower frequency notes.
C) the same frequency notes.
Answer: B
8) Repeatedly tap the side of a drinking glass with a spoon while filling it with water and you
will notice that the pitch of the sound
A) increases.
B) decreases.
C) remains relatively constant.
Answer: B
Test Bank for Conceptual Physical Science
Paul Hewitt, John Suchocki, Leslie Hewitt
9780321752932, 9780134060491
