Physics 20 Mechanical Waves – Practice Multiple Choice Choose the best response and place your answers, using HB pencil, on the Scantron sheet provided.
1. The units of frequency are:
a.
seconds
b.
cycles
c.
Hertz
d.
Tilden
2. The study of what happens to a light ray as it passes from one medium into another is a phenomena called:
a.
diffraction
b.
interference
c.
rarefaction
d.
refraction
3. As shown in the diagram below, a transverse wave is moving with velocity v along a rope. In which direction will
segment X move as the wave passes though it?
a.
c.
down, only
down, then up, then down
b.
d.
up, only
up, then down, then up
4.
Which of the following statements is not characteristics of all waves?
a.
b.
c.
d.
waves transmit energy
waves consist of a series of pulses or disturbances
waves travel in a direction that is at right angles to the vibrating particles of the media
waves are created by a vibrating source
5. The diagram below represents a transverse wave traveling to the right through a medium.
Point A represents a particle of the medium. In which direction will particle A move in the next instant of time?
a.
up
b.
down
c.
left
d.
right
6. A spring is stretched to a length of 7.9 m. You generate a wave in this spring by oscillating your hand back and
forth to create a wave with a 2.7 m wavelength. If the wave takes 3.9 s to travel to the other end of the spring and back
to your hand, what is the frequency of the wave that you generated?
a.
1.3 Hz
b.
1.8 Hz
c.
1.5 Hz
d.
2.1 Hz
7. A 0.982 m long pulse is travelling in a spring. If the pulse takes 0.224 s to pass any point in the spring, how fast is
it travelling?
a.
4.05 m/s
b.
4.87 m/s
c.
4.38 m/s
d.
5.16 m/s
Physics 20 Mechanical Waves – Practice Multiple Choice Use the following information for the next 2 questions:
The diagram represents a wave as it appears on an oscilloscope:
8. The linear distance from point R to point W represents:
a.
2λ
b.
2.5 λ
c.
4λ
d.
4.5 λ
c.
point T
d.
point U
9. The amplitude is from point V to:
a.
point R
b.
point S
10. A wave in a spring moves at a speed of 6.26 m/s. If the frequency of the wave is 2.24 Hz, what is its wavelength?
a.
0.358 m
b.
2.23 m
c.
0.567 m
d.
2.79 m
11. You generate a wave in a spring, stretched out on the floor, by oscillating your hand back and forth at a
frequency of 1.6 Hz. The wave has a 1.5 m wavelength. If the wave takes 2.9 s to travel to the other end of the spring
and back to your hand, what is the length of the stretched spring?
a.
2.9 m
b.
3.5 m
c.
6.4 m
d.
7.0 m
12. Which one of the following statements is a false statement?
a.
b.
c.
d.
e.
Sound waves are longitudinal pressure waves.
Light travels very much faster than sound.
The transverse wave on a vibrating string is different from a sound wave.
Sound waves can travel through a vacuum.
“Pitch” in music is closely related to frequency of a sound wave.
13. A person observes a fireworks display from a safe distance of 0.750 km. Assuming that sound travels at 340 m/s
in air, what is the time between the person seeing and hearing a fireworks explosion?
a.
0.453 s
b.
2.21 s
c.
410 s
d.
2.55 × 105 s
14. The amplitude of a sound wave is to its loudness as the amplitude of a light wave is to its
a.
brightness
b.
frequency
c.
color
d.
speed
Physics 20 Mechanical Waves – Practice Multiple Choice 15. When the source of a sound wave is moving toward an observer, which of the following will appear to occur?
a.
b.
c.
d.
The apparent wavelength of the sound is less than the true wavelength of the sound.
The apparent wavelength of the sound is greater than the true wavelength of the sound.
The apparent speed of the wave is greater than the true speed of the wave.
The apparent speed of the wave is less than the true speed of the wave.
16. The frequency of a vibrating string varies inversely as the string's
a.
c.
b.
d.
length and tension, only
length, diameter, and density, only
length and diameter, only
tension, diameter, and density, only
17. An audio frequency source is attached to the outer edge of a turntable. A student is using an oscilloscope to
measure the frequency of the sound. As the turntable rotates, the oscilloscope indicates that the frequency from the
source increases and decreases
An audio source with a frequency of 622 Hz is attached to the outer edge of a turntable with a radius of 5.20 m and a
period of rotation of 1.10 s. If the speed of sound is 329 m/s, what frequency does the oscilloscope register when the
source is moving directly away from the student?
a.
561 Hz
b.
578 Hz
c.
570 Hz
d.
583 Hz
18. Earplugs work to protect our hearing by reducing a sound wave's:
a.
amplitude
b.
frequency
c.
wavelength
d.
velocity
19. Resonance occurs when one vibrating object transfers energy to a second object causing it to vibrate. The energy
transfer is most efficient when, compared to the first object, the second object has the same natural
a.
frequency
b.
amplitude
c.
loudness
d.
speed
20. Two tuning forks are sounded, one of 254 Hz and the other 256 Hz. The resulting beat frequency will be:
a.
2 Hz
21. I
II
III
IV
a.
b.
4 Hz
c.
255 Hz
d.
510 Hz
d.
II and IV
The angle of incidence and the angle of reflection are equal.
The sines of the angles of incidence and refraction are equal.
The incident ray and the reflected ray are perpendicular.
The incident ray, the reflected ray, and the normal all lie in one plane.
Which statements describe reflection?
I and II
b.
I and IV
c.
II and III
Physics 20 Mechanical Waves – Practice Multiple Choice 22. A ray of light is passing from air into glass. If the angle of incidence, with respect to the normal to the interface, is
increased:
a.
b.
c.
d.
Total internal reflection will occur when the angle of incidence equals the critical angle.
Total internal reflection will occur when the angle of incidence is less than the critical angle.
Total internal reflection will occur when the angle of incidence is greater than the critical angle.
The refractive angle will increase but there will be no total internal reflection.
23. A 4 m long string, clamped at both ends, vibrates at 200 Hz. If the string resonates in six segments, what is the speed
of transverse waves on the string?
a.
100 m/s
b.
133 m/s
c.
267 m/s
d.
328 m/s
e.
400 m/s
24. Closed-Pipe Resonance
A tuning fork held over a closed pipe produces resonance for particular lengths (L). Tuning fork A is held over the end
of the variable-length closed pipe. The length (L) of the pipe is gradually increased. As the pipe gets longer, the sound
of the tuning fork first gets louder, then softer, then louder again. In terms of the wavelength of the sound produced
by the tuning fork, which series of numbers represents possible values for the length of the pipe at which you would
hear the loudest sound?
a.
b.
c.
d.
Physics 20 Mechanical Waves – Practice Multiple Choice 25. The diagram below shows two pulses traveling toward each other in a uniform medium.
Which diagram best represents the medium when the pulses meet at point X?
a.
b.
c.
d.
26. Two pulses, A and B, travel toward each other along the same rope, as shown below.
When the centers of the two pulses meet at point X, the amplitude at the center of the resultant pulse will be
a.
+1 unit
b.
+2 units
c.
0
d.
–1 unit
27. A speaker generates a continuous tone of 440 Hz. In the drawing, sound travels into a tube that splits into two
segments, one longer than the other. The sound waves recombine before being detected by a microphone. The speed of
sound in air is 339 m/s. What is the minimum difference in the lengths of the two paths for sound travel if the waves
arrive in phase at the microphone?
a.
0.10 m
b.
0.39 m
c.
0.77 m
d.
1.11 m
e.
1.54 m
Physics 20 Mechanical Waves – Practice Multiple Choice 28. Which of the following statements applies/apply when a pulse, travelling along an ideal spring, is reflected from
a fixed point at the end of the spring?
I. The amplitude of the reflected pulse is equal to the amplitude of the incident pulse.
II. The length of the reflected pulse is equal to the length of the incident pulse.
III. The speed of the reflected pulse is equal to the speed of the incident pulse.
a.
I and II
b.
II and III
c.
I and III
d.
I, II, and III
29. Two waves having the same amplitude and frequency are traveling in the same medium. Maximum destructive
interference will occur when the phase difference between the waves is
a.
0°
b.
90°
c.
180°
d.
270°
30. Two-point Interference Pattern
Two in-phase point sources in a ripple tank, S1 and S2, generate the interference pattern shown below. S1 and S2 are
4λ apart. The maxima and minima are labeled from K to R.
If 1.36-cm wavelengths are generated at the sources, how much farther from S2 than S1 are the points on line K?
a.
2.72 cm
b.
4.08 cm
c.
3.40 cm
d.
4.76 cm
d.
phase
31. A change in the speed of a wave as it enters a new medium produces a change in
a.
frequency
b.
period
c.
wavelength
Physics 20 Mechanical Waves – Practice Multiple Choice 32. Refer to the diagram
Listed below are four pairs of points from the wave train diagram. Which of the pairs of points are in phase?
I.
II.
III.
IV.
a.
A and J
G and N
E and N
C and L
I, II, and III
b.
I, III, and IV
c.
I, II, and IV
d.
II, III, and IV
33. Two traveling pulses on a rope move toward each other at a speed of 1.0 m/s. The waves have the same amplitude.
The drawing shows the position of the waves at time t = 0 s. Which one of the following drawings depicts the waves on
the rope at t = 2.0 s?
a.
b.
c.
d.
e.
f.
Physics 20 Mechanical Waves – Practice Multiple Choice 34. Refer to the diagram
The labelled points that are located at nodal points are
a.
A and C
b.
A, C, and E
c.
B and D
d.
E only
35. If the angle between an incident ray and reflected ray is 70o, the angle of reflection is:
a.
15o
b.
20o
c.
35o
d.
140o
36. A wave travels from one medium to a different medium, with a resulting decrease in the wave speed. Along with
this decrease in speed there is a
a.
b.
c.
d.
e.
decrease in the wavelength of the wave, the frequency remaining constant.
decrease in the frequency of the wave, the wavelength remaining constant.
decrease in both the wavelength and frequency of the wave.
increase in the wavelength of the wave and a decrease in its frequency.
increase in the frequency of the wave and a decrease in its wavelength.
37. A ray of monochromatic light traveling in air is incident on a plane mirror at an angle of 30.°, as shown in the
diagram below.
The angle of reflection for the light ray is
a.
15°
b.
30°
c.
60°
d.
90°
Physics 20 Mechanical Waves – Practice Multiple Choice 38. The diagram depicts a sketch of an observation that students made during an experiment with a ripple tank.
The students set up the tank so that the wave fronts travelling from the straight wave generator crossed a line at which
the depth of the water changed. Which of the following statements correctly describes the waves as they pass over the
line where the depth changes?
I.
II.
III.
IV.
a.
The frequency of the waves is unchanged.
The frequency of the waves decreases.
The speed of the waves is unchanged.
The speed of the waves increases.
I and III
b.
II and III
c.
I and IV
d.
II and IV
39. Which diagram best represents the shape and direction of a series of wave fronts after they have passed through
a small opening in a barrier?
a.
b.
c.
d.
40. Two-point Interference Pattern
Two in-phase point sources in a ripple tank, S1 and S2, generate the
interference pattern shown below. S1 and S2 are 4λ apart. The maxima and
minima are labeled from K to R.
If the frequency of the sources is gradually increased, which of the
following would occur?
I. The distance between lines P and Q would increase.
II. The number of maxima and minima would increase
.III. The number of wavelengths between the sources would increase.
a.
I and II
b.
II and III
c.
I and III
d. I, II, and III