Oscillators, Waves, Sound
For every question, also consider as a possible answer
E) none of the above
Possibly useful information:
v = x /
t
p = m v
T = 2
a = v /
t
PE = m g
h
T = 2
v = vi + a t PE
= (1/2) k x2
v
=
x = xi + vi t + (1/2)
a t2 KE
= (1/2) m v2
v=(wavelength)
x (frequency)
v = r
F = k x
L = (n) x
(half wavelength)
F = m a Ei
= Ef
F12 = - F21 pi
= pf
w = mg F
=
p /
t
g = 9.8 m/s2
10 m/s2
For every question, also consider as a possible answer
E) none of the above
E) none of the above
1. Increasing the amplitude of a mass-and-spring simple harmonic oscillator makes its period
A) longerB) shorter
C) unchanged;
As with all simple harmonic oscillators, the period is independent of the amplitude
2. Increasing the mass m of a mass-and-spring simple harmonic oscillator makes its period
A) longer ; T = 2![]()
B) shorter
C) unchanged
3. Increasing the spring constant k of a mass-and-spring simple harmonic oscillator makes its period
A) longerB) shorter ; T = 2
; increasing k decreases T
C) unchanged
4. A mass-and-spring simple harmonic oscillator has maximum kinetic energy
A) at its equilibrium positionAt its equilibrium position the potential energy is zero, PE = (1/2) k x2so the kinetic energy is at its maximum
B) when its displacement equals its amplitude
PE = max for x = AmplitudeC) half way between equilibrium and amplitude
D) two-thirds of the way between equilibrium and amplitude
5. A mass-and spring simple harmonic oscillator has maximum potential energy at
A) at its equilibrium positionPE = 0 for x = 0B) when its displacement equals its amplitude
PE = max for x = AmplitudeC) half way between equilibrium and amplitude
D) two-thirds of the way between equilibrium and amplitude
6. The amplitude of a simple harmonic oscillator is
A) the time required for one oscillationB) the number of oscillators per second
C) the energy stored in the oscillations
D) the maximum distance moved from equilibrium
7. The period of a simple pendulum depends upon its
A) massB) amplitude
C) length; T = 2
D) all of the above
The period depends only upon the length and the acceleration of gravity.The period of any simple harmonic oscillator is independent of the amplitude.
The period of a pendulum is independent of the mass.
8. The period of a certain simple harmonic oscillator is 0.01 s; its frequency is
A) 0.1 HzB) 1.0 Hz
C) 10.0 Hz
D) 100.0 Hz; f = 1/T = 1/0.01 s = 100 /s = 100 Hz
9. The frequency of a certain oscillator is 50 Hz; it's period is
A) 0.2 sB) 0.02 s ; T = 1 / f = 1 / 50 Hz = 0.02 s
C) 0.002 s
D) 0.0002 s
10. If you apply a force to an oscillator at its natural frequency, you will produce motion
A) at exactly twice that frequencyB) at exactly one-half that frequency
C) with large amplitude
This is the whole idea of resonance.D) with an amplitude that dies out or gets smaller.
11. There are "signals" of many different frequencies coming into the antenna of your radio. Only the one with a particular frequency is amplified and produces the sound you listen to. This is an example of
A) dampingB) amplitude degeneration
C) timbre or quality
D) resonance
12. Where is the speed of a simple harmonic oscillator zero?
A) at its equilibrium positionB) when its displacement equals its amplitude
Here, at max displacement, the PE is max and KE is zeroKE = 0 requires v = 0
C) half way between equilibrium and amplitude
D) two-thirds of the way between equilibrium and amplitude
13. Like a transverse wave, a longitudinal wave has a/an
A) amplitudeB) wavelength
C) period
D) all of the above
14. Which of the following is a longitudinal wave?
A) lightB) wave on a string
C) sound
D) all of the above
15. The individual vibrations or disturbances of a longitudinal wave move
A) in the same direction as the wave itselfB) perpendicular to the wave itself
16. A wave has a frequency of 20 Hz and travels 5 m in one second. It has
A) a wave speed of 100 m/s and a wavelength of 4 m.B) a wave speed of 100 m/s and a wavelength of 1/4 m.
C) a wave speed of 5 m/s and a wavelength of 1/4 m
v is given; the wave "travels 5 m in one second."v = 5 m/sv = (frequency) x (wavelength)
5 m/s = 20 (1/s) x [wavelength]
5 m/s = 20 (1/s) x [ (1/4) m]
wavelength = (1/4) mD) a wave speed of 5 m and a wavelength of 4 m
17. For standing waves, nodes are
A) always a wavelength apart; nodes are always half a wavelength apartB) regions of greatest amplitude;
nodes are regions of smallest amplitude -- zeroantinodes are regions of greatest amplitude
C) regions of greatest frequency
everything on a standing wave has the same frequencyD) always two wavelengths apart ; nodes are always half a wavelength apart
E) none of the above
18. For standing waves, antinodes
A) are a wavelength apart ; antinodes are always half a wavelength apartB) have the greatest frequency
everything on a standing wave has the same frequencyC) alternate with nodes
D) all of the above
19. For standing waves on a string,
A) a node is located at each endB) a whole number times half the wavelength equals the length of the string
C) the whole "pattern" of standing waves occurs only for certain frequencies
D) all of the above
20. On a string that is 2.0 m long, standing waves may be formed with the following wavelengths:
(Yes, the fundamental frequency will have a wavelength of 4.0 m).
A) 4.0 m, 2.0 m, 0.5 mB) 4.0 m, 2.0 m, 1.5 m
C) 4.0 m, 1.5 m, 0.75 m
D) 4.0 m, 1.67 m, 0.67 m
L = n x (half a wavelength)n = any integerhalf a wavelength = L / n
wavelength = 2 L / n
L = 2.0 m
wavelength = 2 x 2.0 m / n = 4.0 m / n
wavelength = 4 m, (4/2) m, (4/3) m, (4/4) m, (4/5) m,
(4/6) m, (4/7) m, (4.8) m, etc wavelength = 4.0 m, 2.0 m, 1.33 m, 1.00 m, 0.80 m,
0.67 m, 0.57 m, 0.50 m, etc
21. Standing waves can occur when
A) the frequency equals the wavelengthB) the amplitude exceeds the wavelength
C) a wave's frequency is supersonic
D) a wave's period equals its wavelength
E) none of the above
22. An antinode is
A) always in the middle of a standing waveB) a position of maximum amplitude
C) a position of minimum amplitude;
a node is a position of minimum amplitude (zero)D) equal to the fundamental frequency
23. Light and sound are both waves. You may see bolt of lightning long before you hear its thunder. This is because
A) of resonanceB) light travels faster than sound
C) sound requires air to be transmitted and light does not
D) light passes through humid air but sound does not
24. A bobber on a fishing line oscillates up and down four times per second as waves pass by. The waves have a frequency of
A) (1/4) HzB) 4 Hz
C) (1/4) sec
D) 4 sec
25. A bobber on a fishing line oscillates up and down three times per second as waves pass by. The waves have a wavelength of 20 cm. The waves are traveling at
A) 20 cm/sB) 40 cm/s
C) 60 cm/s
v = (frequency) x (wavelength)v = ( 3 Hz ) x ( 20 cm)
v = 60 cm/s
D) 80 cm/s
26. If you put your fingertip in a pool of water and repeatedly move it up and down, you will create circular water waves that move out from that point. What will happen to the wavelength of these waves if you move your finger up and down more slowly (or less frequently)?
A) increasev = (frequency) x (wavelength)Decreasing frequency means increasing wavlength.
B) remain the same
C) decrease
27. Sound is
A) an electromagnetic waveB) a polarized wave; only a transverse wave can be polarized
C) a longitudinal wave
D) all of the above
28. Light is or may be
A) an electromagnetic wave; light is always an EM waveB) a polarized wave; because light is a transverse wave, it may be polarized
C) a transverse wave; light is always a transverse wave
D) all of the above
29. "Supersonic" means
A) lower than the range of human hearingB) higher than the range of human hearing
C) faster than the speed of sound
D) slower than the speed of sound
30. "Ultrasonic" means
A) lower than the range of human hearingB) higher than the range of human hearing
C) faster than the speed of sound
D) slower than the speed of sound
31. Bats and dolphins use echolocation to navigate or the find food or to find their way without relying on sight. The frequencies they use are
A) supersonicB) infrasonic
C) ultrasonic
D) microsonic
32. If you double the frequency of a sound wave, you also double its
A) wavelength; if you double the frequency, you cut the wavelength in halfB) speed; the speed is independent of the frequency
C) amplitude; the amplitude and frequency do not depend upon each other
D) all of the above
E) none of the above
33. The range of human hearing is about
A) 10 Hz to 100 HzB) 50 Hz to 500 Hz
C) 50 Hz to 20 000 Hz
D) 1 000 Hz to 100 000 Hz
34. Sound travels fastest in
A) air (a gas)B) water (a liquid)
C) aluminum (a solid)
D) vacuum
35. The speed of sound in air depends upon
A) wavelengthB) frequency
C) temperature
D) amplitude
36. Increasing the length of a vibrating string will
A) decrease its resonance frequencyIncreasing the length means increasing the wavelength of the resonance and increasing the wavelength means decreasing the frequencyB) decrease its amplitude
C) increase its amplitude
D) increase its resonance frequency
37. Ella Fitzgerald made commercials for Memorex in which she used her voice to break a wine glass. This is an example of
A) echolocationB) reflected sound
C) ultrasonic frequencies
D) resonance
38. Beats are heard when two sounds have
A) nearly the same amplitudeB) nearly the same frequencies
C) twice the amplitude
D) exactly twice the frequency
39. The fundamental frequency present in a sound is the
A) sum of all the frequencies mixed togetherB) difference between the highest and lowest frequencies present
C) lowest frequency present
D) highest frequency present
40. The fundamental frequency present in a sound determines the
A) quality or timbreB) amplitude or loudness
C) pitch or note
D) none of the above
41. The "pitch" of a sound is determined by its
A) overtones frequenciesB) harmonics frequencies
C) fundamental frequency
D) resonance frequencies
42. The quality or timbre -- the distincitive characteristic -- of a sound is determined by its
A) overtones or harmonicsB) amplitude or loudness
C) attack or decay
D) fundamental frequency
43. You hear beats with a frequency of 2 Hz when you strike a tuning fork that vibrates at 440 Hz and a chime. The chime has a frequency of
A) 440 x 2 Hz = 880 HzB) 442 Hz
The beat frequency is the difference in the two frequencies.C) (440 / 2) Hz = 220 Hz
D) 110 Hz
44. The fundamental frequency of a violin string is 440 hertz. The frequency of its second harmonic is
A) 110 HzB) 220 Hz
C) 440 Hz
D) 880 Hz
45. Consider a musical note of 220 hertz ("A" below the staff). Two octaves higher is represented by a musical note of
A) 110 Hz; This is one octave lower.B) 440 Hz; This is one octave higher.
C) 660 Hz
D) 880 Hz
46. The intensity or loudness of a musical sound is related to the sound wave's
A) wavelengthB) frequency
C) amplitude
D) wave speed
47. Suppose you play a note of a certain pitch on a violin. You can produce a higher-pitched note by
A) shortening the length of the string that is allowed to vibrateB) decreasing the tension of the string (loosening the string)
C) increasing the linear mass density of the string (using a "heavier" string)
D) lengthening the part of the string that vibrates.
48. Consider the sound made when you blow across the open top of a soda bottle. Now pour some water into the soda bottle and again blow across the open top of the bottle. With the additional water now in the bottle, you should expect the pitch of the sound produced to be
A) higherThe additional water means the column of air which resonates is shorter.This means the standing wave has a shorter wavelength.
And a shorter wavelength means a higher frequency.
B) lower
49. When a flute sound is viewed on an oscilloscope, the sound wave is very smooth. This is because
A) the amplitude is always small (flutes are quiet)B) it has practically no overtones
C) its fundamental frequency has a smaller amplitude than its second and third harmonics
D) its harmonics get larger and larger
50. When a trumpet sound is viewed on an oscilloscope, the sound wave is very complex. This is because
A) the amplitude is always large (trumpets are loud)B) it has practically no overtones
C) it has many overtones
D) its has only even-numbered overtones
(C) 1998 Doug Davis, all rights reserved