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Flashcards in Oscillations and Waves Deck (67):
1

The frequency of oscillation f of a mass m suspended from a vertical spring is given by f= (1/2pi)(k/m)^(1/2)
where k is the spring constant.
Which one of the following plots would produce a straight-line graph?
A. f against m
B. f2 against 1/m
C. f against (m)^(1/2)
D. 1/f against m

B. f2 against 1/m

2

A mass is suspended from a vertical spring. It is set into oscillation by pulling it down a short distance and then releasing it. At which one of the labelled points, during the subsequent motion, will the
acceleration be zero? 

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C

3

When light waves travel from air to glass which one of the following happens to the frequency and
wavelength of the light?

           Frequency                  Wavelength

A. stays the same              decreases

B. decreases                       increases

C. stays the same             increases

D. increases                     decreases

A. the frequency stays the same and the wavelength decreases

4

A ray of light travelling in glass is incident on the glass-air boundary at an angle pheta to the normal as shown in the diagram. If pheta is greater than the critical angle which one of the rays best shows the path of the ray?

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D

5

Which one of the following correctly places the named parts of the electromagnetic spectrum in order of
increasing wavelength?
A. y-rays, radio waves, x-rays, ultra-violet rays
B. y-rays, x-rays, ultra-violet rays, radio waves
C. radio waves, ultra-violet rays, x-rays, y-rays
D. ultra-violet rays, x-rays, y-rays, radio waves

B. y-rays, x-rays, ultra-violet rays, radio waves

6

The diagram shows two loudspeakers connected to the same signal generator. As a microphone is moved along the path XY a series of maximum and minimum sound levels is detected.

Which one of the following actions on its own will increase the separation between the maximum and
minimum sound levels?
A. Moving the speakers closer to the line XY.
B. Increasing the separation between the speakers.
C. Increasing the amplitude of the sound waves.
D. Decreasing the frequency of the sound waves.

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D. Decreasing the frequency of the sound waves.

7

A vibrating string has a length of L. If the speed of the waves in the string is c the frequency of the fundamental mode of vibration of the string will be
A. 2L/c
B. c/L
C. c/2L
D. 2c/L

C. c/2L

8

The diagram represents, at a particular instant of time, a transverse wave travelling to the right along a rope. One section of rope has been marked by tying a ribbon around it at point P.

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C

9

Light is incident from air onto on a glass block. What happens to the frequency and wavelength of the light on entering the glass?

                               Frequency                       Wavelength

A.                           changes                                 changes

B.                           changes                              unchanged

C.                           unchanged                         changes

D.                          unchanged                           unchanged

C. frequency doesn't change while wavelength changes

10

Monochromatic light incident on two narrow parallel slits produces a fringe pattern on a screen, with the intensity distribution shown below.

If the same slits were spaced further apart, which of the following diagrams best shows the intensity distribution pattern that would result?

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C

11

The diagram below shows ripples on the surface of water at one instant of time. The ripples are moving right to left and a small object, P, is floating in the water. After a quarter of a time period, which letter
correctly shows the position of the floating object?

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A

12

Light is refracted at the interface between air and a material as shown below.

The table below lists the value for the sine of various angles.

Angle         0°      30°   45°   60°   90°
Sin (angle) 0.00 0.50 0.71 0.87 1.00
 

Which one of the following is the best estimate for the refractive index of the material?
A. 0.8
B. 1.2
C. 1.4
D. 1.7

C. 1.4

13

Two waves of equal frequency, wavelength and amplitude, A, are travelling along a string towards the same point P as shown below.

If the waves arrive at P at the same time, which of the following best describes the subsequent motion of the string at point P?
A. It will not move.
B. It will oscillate with amplitude A.
C. It will oscillate with amplitude 2 A.
D. It will oscillate with varying amplitude.

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A. It will not move

14

An organ pipe is closed at one end and open at the other as shown below.

Which one of the following diagrams correctly shows the positions of the displacement nodes and antinodes when the fundamental standing wave is formed in the tube?

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C

15

Water waves at the surface of a pond pass a floating log of length L. The log is at rest relative to the bank. The diagram shows wave crests at one instant.

The number of crests passing the log per unit time is N. The speed of the water waves relative to the log at rest is
A. (L/7)(N-1)

B. (L/6)(N-1)

C. (L/7)N

D. (L/6)N

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B. (L/6)(N-1)

16

Two identical triangular pulses of amplitude X travel toward each other along a string. At the instant shown on the diagram below, point M is midway between the two pulses. 

The amplitude of the disturbance in the string as the pulses move through M is
A. 2X.
B. X.
C. X/2
D. 0.

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D. 0

17

A person is walking along one side of a building and a car is driving along another side of the building.

The person can hear the car approach but cannot see it. This is explained by the fact that sound waves
A. travel more slowly than light waves.
B. are diffracted more at the corner of the building than light waves.
C. are refracted more at the corner of the building than light waves.
D. are longitudinal waves.

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B. are diffracted more at the corner of the building than light waves

18

A pulse is sent down a string fixed at one end. Which one of the following diagrams best represents the reflected pulse?

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C

19

Waves can be reflected, refracted and diffracted. Which of these effects can be explained using Huygens’ principle?
A. reflection, refraction and diffraction
B. reflection and refraction only
C. refraction and diffraction only
D. reflection and diffraction only

A. reflection, refraction, and diffraction

20

The displacement d of a particle in a wave varies with distance x along a wave and with time t as shown below.

Which expression gives the speed of the wave?

A.  l/4r

B. l/2r

C. l/r

D. 2l/r

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B l/2r

21

A plane wave approaches and passes through the boundary between two media. The speed of the wave in medium 1 is greater than that in medium 2. Which one of the following diagrams correctly shows the wavefronts?

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A

22

Two particles X and Y are situated a distance (1/2)λ apart on a stationary wave of wavelength λ. The variation with time t of the displacement of X is shown below.

Which one of the following correctly shows the variation with time t of the displacement of particle Y?

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A

23

The diagram shows the variation with distance x along a wave with its displacement d. The wave is travelling in the direction shown.

The period of the wave is T. Which one of the following diagrams shows the displacement of the wave at a time T/4 later?

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B

24

When a wave crosses the boundary between two media, which one of the following properties of the wave does not change?
A. Amplitude
B. Wavelength
C. Frequency
D. Speed

C. Frequency

25

A pipe, open at both ends, has a length L. The speed of sound in the air in the pipe is v. The frequency of vibration of the fundamental (first harmonic) standing wave that can be set up in the pipe is

A. v/2L

B. L/2v

C. 4v/L

D. L/4v

A. v/2L

26

Jeremy is walking alongside a building and is approaching a road junction. A fire engine is sounding its siren and approaching the road along which Jeremy is walking. 

Jeremy cannot see the fire engine but he can hear the siren. This is due mainly to
A. reflection.
B. refraction.
C. the Doppler effect.
D. diffraction.

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D

27

On which one of the following graphs is the wavelength and the amplitude a of a wave correctly represented?

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D

28

Standing waves in an open pipe come about as a result of
A. reflection and superposition.
B. reflection and diffraction.
C. superposition and diffraction.
D. reflection and refraction.

A

29

A source of sound approaches a stationary observer. The Doppler effect may be described by the observer as
A. the increase in loudness of the sound.
B. the increase in wavelength of the sound.
C. the increase in frequency of the sound.
D. the increase in relative speed of the sound waves.

C. the increase in frequency of the sound

30

The diagram below shows two wave pulses moving towards one another.

Which one of the following diagrams shows the resultant pulse when the two pulses are superposed?

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B

31

What change, if any, occurs in the wavelength and frequency of a light wave as it crosses a boundary from air into glass?
              Wavelength          Frequency
A. Decreases Decreases
B. Decreases Unchanged
C. Increases Increases
D. Increases Unchanged

B. wavelength decreases, but frequency stays unchanged

32

The variation with time t of the separate displacements d of a point in a medium due to two waves are shown below.

The waves are superposed. Which of the following diagrams shows the variation with time t of the resultant displacement d of the point in the medium?

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A

33

A loudspeaker emits sound of frequency f. The sound waves are reflected from a wall. The arrangement is shown below.

When a microphone is moved along the line SW, minimum loudness of sound is detected at points P, Q and R. There are no other minima between these points. The separation of the minima is d.
The speed of the sound wave is

A. (1/2) fd

B. f/d

C. fd

D. 2fd

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D. 2fd

34

The wavelength of a progressive transverse wave is defined as
 A. the distance between a crest and its neighbouring trough.
 B. the distance between any two crests of the wave.
 C. the distance moved by a wavefront during one oscillation of the source.
 D. the distance moved by a particle in the wave during one oscillation of the source.

C. the distance moved by a wavefront during one oscillation of the source.

35

The two graphs show the variation with time of the individual displacements of two waves as they pass through the same point.

The displacement of the resultant wave at the point at time T is equal to

A. x1 + x2

B. x1 - x2

C. A1 + A2

D. A1 - A2

B

36

Which one of the following is not a true statement about a standing wave in one dimension?
 A. A standing wave is formed by the superposition of two progressive waves.
 B. A standing wave stores energy but does not transfer it.
 C. The wavelength of the standing wave is the distance between adjacent nodes.
 D. The amplitude of vibration varies along the standing wave

C. The wavelength of the standing wave is the distance between adjacent nodes.

37

The graph below shows the variation of air pressure with distance along a wave at one given time. The arrow indicates the direction of travel of the wave.

The air pressure at point P is
 A. increasing.
 B. decreasing.
 C. constant.
 D. zero.

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B. decreasing

38

Sound waves move faster in warm air than in cold air. The diagram below shows plane waves in cold air moving towards a boundary with warm air.

Which of the arrows shows the possible direction of waves after reaching the boundary?
 A. I
 B. II
 C. III
 D. IV

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C. III

39

The speed of sound in still air is c. A source of sound moves away from an observer at speed v. What will be the speed of sound as measured by the observer?
 A. c
 B. c + v
 C. c – v
 D. v – c

A. c

40

The fundamental frequency of a pipe closed at one end is f. A pipe of the same length but open at both ends has a fundamental frequency (first harmonic) of
 A. (1/2) f
 B. f.
 C. 2f.
 D. 4f

C. 2f

41

Diagram 1 below shows the displacement of part of a medium through which a wave is travelling at time t = 0. Diagram 2 shows the displacement at a later time t = 4.0 s in which the wave has moved
forward 10 cm. In this time, the point P on the wave has moved from a crest through zero displacement to a trough

The wavelength of the wave is
 A. 5.0 cm.
 B. 10 cm.
 C. 20 cm.
 D. 40 cm.

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C. 20 cm

42

The diagram below shows a pulse travelling along a rope from X to Y. The end Y of the rope is tied to a fixed support

When the pulse reaches end Y it will
 A. disappear.
 B. cause the end of the rope at Y to oscillate up and down.
 C. be reflected and be inverted.
 D. be reflected and not be inverted. 

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C. be reflected and be inverted.

43

Which one of the following is correct for transfer of energy along a standing wave and for amplitude of vibration of the standing wave?

Transfer of energy along                    
a standing wave
                                                     Amplitude of vibration of
                                                      the standing wave
A. None                                    Constant amplitude
B. None                                     Variable amplitude
C. Energy is transferred            Constant amplitude
D. Energy is transferred           Variable amplitude

B. there is no transfer of energy and the amplitude varies

44

Two pipes P and Q are of the same length. Pipe P is closed at one end and pipe Q is open at both ends. The fundamental frequency (first harmonic) of the closed pipe P is 220 Hz. The best estimate for the fundamental frequency of the open pipe Q is
 A. 880 Hz.
 B. 440 Hz.
 C. 110 Hz.
 D. 55 Hz. 

B. 440 Hz

45

A source produces water waves of frequency 10 Hz. The graph shows the variation with horizontal position of the vertical displacement of the surface of water at one instant in time.

The speed of the water waves is
 A. 0.20 cm s−1
.
 B. 4.0 cm s−1
.
 C. 10 cm s−1
.
 D. 20 cm s−1

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D

46

A wave travels from one medium to another. Which of the following is true about its frequency and wavelength?

Frequency Wavelength
A. No change No change
B. Change No change
C. No change Change
D. Change Change

C. there is no change in the frequency and there is a change in the wavelength

47

A bat approaches an insect of wing span length d. The bat emits a sound wave. The bat detects the insect if the sound is reflected from the insect.

The insect will not be located if
 A. the insect’s speed is less than the speed of the sound wave.
 B. the insect’s wing beat frequency is greater than the frequency of the sound wave.
 C. the length d is much greater than the wavelength of the sound wave.
 D. the length d is much smaller than the wavelength of the sound wave

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D. the length d is much smaller than the wavelength of the sound wave.

48

The speed of sound in air at room temperature is v. An organ pipe of length l is closed at one end. The frequency of the fundamental (first harmonic) of the sound emitted by the pipe is

A. v/4l

B. v/2l

C. v/l

D. vl

A. v/4l

49

The diagram below shows a transverse wave on a string. The wave is moving from right to left.

In the position shown, point X has zero displacement and point Y is at a position of maximum displacement. Which one of the following gives the subsequent direction of motion of point X and
of point Y?

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D

50

Light is incident on an air-glass boundary as shown below.

Which one of the following is a correct statement of Snell’s law?
 A. sinP= constant × sinR
 B. sinP= constant × sinS
 C. sinQ= constant × sinR
 D. sinQ= constant × sinS

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D. sinQ= constant × sinS

51

Which one of the following correctly describes wave speed when referring to a standing wave?
 A. The difference in speed of the two travelling waves that give rise to the standing wave.
 B. The speed of one of the travelling waves that gives rise to the standing wave.
 C. The speed of transfer of energy between neighbouring internodal loops of the standing wave.
 D. Maximum speed of a particle at an antinode of the standing wave.

B. The speed of one of the travelling waves that gives rise to the standing wave.

52

A    string    is    held    horizontally    with    one    end    attached    to    a    fixed    support.        Two    pulses    are    created    at    the    free    end    of    the    string.        The    pulses    are    moving    towards    the    fixed    support    as    shown    in    the    diagram    
below.

Which one of the following diagrams is a possible subsequent picture of the string?

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C

53

A water surface wave (ripple) is travelling to the right on the surface of a lake. The wave has period T. The diagram below shows the surface of the lake at a particular instant of time. A piece of cork is
floating    in    the    water    in    the    position    shown. Which is the correct position of the cork a time T/4 later?

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A

54

The diagram below shows a photograph of part of a standing wave    on    a    string    that    is    fixed    at    both    ends. The wavelength of the wave is 40 cm. At a particular time the point marked P has displacement + 2.0 cm and moves with velocity + 80 m s–1.

A second point Q on the string is at a distance of 20cm from P. At the same time that the photograph above was taken, the displacement and velocity of point Q were
    displacement velocity
A. + 2.0 cm + 80 m s–1
B. + 2.0 cm – 80 m s–1
C. – 2.0 cm + 80 m s–1
D. – 2.0 cm – 80 m s–1

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D

55

A source of sound is placed near the open end of a cylindrical tube that lies on a horizontal table. The tube has some powder sprinkled along its length. The powder collects in piles along the length
of the tube as shown below.

The distance between two consecutive piles of powder is d and the speed of sound in the tube is v. The frequency of the source is

A. v/2d

B. v/d

C. dv

D. 2dv

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A. v/2d

56

A wave is travelling through a medium. The diagram shows the variation with time t of the displacement d of a particle of the medium from t = 0 to t = 25 ms.

Which of the following correctly gives the frequency and the amplitude of the wave?

frequency / hz         amplitude / cm
A. 2.0 x 10–2        2.0
B. 2.0 x 10–2         1.0
C. 50                  2.0
D. 50               1.0

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D

57

Waves of frequency f travel with speed c in air and enter a medium M of refractive index 1.5. Which of the following correctly gives the frequency and speed of the waves in the medium M?

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A

58

Pipe X of length 3.0 m is open at both ends. It produces a note of frequency 28 Hz when the air in the pipe    vibrates    in    its    fundamental    (first    harmonic)    mode.    
Pipe Y is closed at one end and also produces a note of frequency 28 Hz when the air in the pipe vibrates in its fundamental mode. The best estimate for the length of pipe Y is
 A. 12 m.
 B. 6.0 m.
 C. 3.0 m.
 D. 1.5 m

D

59

Plane wavefronts are incident on a barrier as shown below. Which of the following best shows the shape of the wavefronts on the other side of the barrier?

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A

60

Which of the following best describes the wave speed of a progressive wave travelling through a
medium?
 A. The maximum speed of the vibrating particles of the medium
 B. The average speed of the vibrating particles of the medium
 C. The speed of the medium through which the wave travels
 D. The speed of transfer of energy through the medium

D. The speed of transfer of energy through the medium

61

Which of the following diagrams best shows the path of a ray of monochromatic light through a glass prism in air?

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B

62

Plane parallel wavefronts are incident on an obstacle. Which of the following diagrams best shows the diffraction of the waves around the obstacle?

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B

63

A vibrating tuning fork is held above the top of a tube that is filled with water. The water gradually runs out of the tube until a maximum loudness of sound is heard. Which of the following best shows the standing wave pattern set up in the tube at this position?

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C

64

The phenomenon of diffraction is associated with
 A. sound waves only.
 B. light waves only.
 C. water waves only.
 D. all waves.

D

65

The diagram below shows plane wavefronts of a wave that is approaching the boundary between two media, X and Y. The speed of the wave is greater in medium X than in medium Y. The wave
crosses the boundary.

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A

66

The graph below shows the variation with time t of the separate displacements d of a medium, at a particular point in the medium due to two waves, P and Q.

The amplitude of the wave resulting from the interference of P and Q is
 A. 0.0 mm.
 B. 1.0 mm.
 C. 1.4 mm.
 D. 2.0 mm.

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C. 1.4 mm

67

One end of a long string is vibrated at a constant frequency f . A travelling wave of wavelength λ and speed v is set up on the string.
The frequency of vibration is doubled but the tension in the string is unchanged. Which of the following shows the wavelength and speed of the new travelling wave?
                   Wavelength                             speed
A. λ/2                        v
B. λ/2                         2v
C. 2λ                        v
D. 2λ                       2v

A