(03)waves revision mc test

Physics – Waves Revision Mc Test Time allowed: 3 hours Multiple Choice Questions

1 Peter saw that a small foam board floated on the water surface in a harbour. Then there was a water wave travelled from north to south across the board. The foam board moved (1) to north. (2) to south. (3) up and down only. A. (1) only B. (2) only C. (3) only D. (1) and (2) only

2 During a tennis match, Sally paces back and forth along the sideline 8 times in 1 minute. What is the

frequency of her pacing? A. 8 Hz B. 0.125 Hz C. 0.133 Hz D. 7.5 Hz

3 Near a 2 m long bath tub containing some water, a child drops a soap at one end of the bath tub and

hence produces a water wave. The wave takes 4 s to travel along the tub and back. Find the speed of the water wave. A. 0.25 m s−1 B. 0.5 m s−1 C. 1 m s−1 D. 2 m s−1

4 The diagram shows a displacement-time graph of a particle of a transverse wave.

If the wavelength of the wave is twice the magnitude of amplitude, what is the speed of the wave? A. 0.1 m s−1 B. 0.5 m s−1 C. 1 m s−1 D. 10 m s−1

(03)Waves Revision MC Test.doc 1

5 The speed of a wave is affected by A. the properties of the medium through which the wave travels. B. the wavelength of the wave. C. the frequency of the wave. D. both the wavelength and frequency of the wave.

6 Two waves are produced by a vibrator. Waves A and B have wavelengths of 1 m and 3 m respectively.

The speed of wave B is ________ that of wave A. A. one-ninth B. one-third C. the same as D. three times

7 Which of the following is not a characteristic of mechanical waves?

A. They transport energy. B. They are created by vibrating sources. C. They do not transfer matters. D. They are transverse waves.

8 Which of the following statements about longitudinal wave is correct?

A. Particles vibrate at right angles to the movement of the wave. B. Particles move in the same direction to the propagation of the wave. C. Particles sometimes move in the opposite direction to the propagation of the wave. D. No transmission medium is required.

9 In the following wave, which interval represents one wavelength of the wave?

A. A to D B. A to G C. C to E D. C to F


10

Which of the following shows the wave after a quarter of period? A.

B.

C.

D.

11 In a water wave, the horizontal distance between two adjacent particles having the highest and lowest speed is 6 cm. Find the wavelength of the wave. A. 3 cm

B. 6 cm C. 12 cm D. 24 cm

12 If two waves are of the same frequencies, which of the following characteristics is identical for the

waves? A. Phase B. Wavelength C. Amplitude D. Period


13 What is the wavelength of the wave shown?

A. 5 cm B. 10 cm C. 15 cm D. 20 cm

14 What is the frequency of the wave shown?

A. 0.2 Hz B. 0.5 Hz C. 5 Hz D. 10 Hz

15 One end of a slinky spring is attached to a wall. Simon applied different forces to produce two pulses of

different amplitudes and wavelengths in the spring. Which of the following is correct? A. The pulse with a higher amplitude will travel at a higher speed. B. The pulse with a longer wavelength will travel at a higher speed. C. The pulse with a larger applied force will travel at a higher speed. D. The two pulses travel at the same speed.

16 Two waves are produced by a vibrator. Wave A has an amplitude larger than wave B . The energy

transported by wave A is __________ that transported by wave B. A. larger than B. the same as C. smaller than D. It cannot be determined.


17

Which of the following statements about the water wave shown is / are true? (1) Particle S is moving upwards. (2) The length of RS represents the amplitude of the wave. (3) Particle P will move to the position of particle R after half a period. A. (1) only B. (2) only C. (3) only D. (1) and (2) only

18 In a water wave of period 5 s, the horizontal distance between two adjacent particles having the

highest and lowest speed is 3 m. Find the speed of the wave. A. 0.6 m s−1

B. 1.2 m s−1 C. 1.67 m s−1 D. 2.4 m s−1

19 In a transverse wave, the vertical distance between two nearest particles which have the maximum

magnitude of displacement from their equilibrium positions is equal to A. twice the amplitude of the wave. B. the amplitude of the wave. C. half the wavelength of the wave. D. the wavelength of the wave.

20 Which of the following about a particle of a wave in one period is correct?

A. The particle moves a distance of one wavelength. B. The particle moves a distance of one amplitude. C. The particle has a displacement of four amplitudes. D. The particle has no displacement.


21

The diagram shows a wave moving through a rope towards the right. If this wave meets another identical wave moving in the opposite direction, which of the following diagrams shows a pattern which could never appear in the rope? A.

B.

C.

D.

22 When a plane wave travels through two straight barriers with a gap between them, some of the wave

are diffracted while some are reflected. Which of the following is / are correct? (1) The wavelength and speed of both the diffracted and reflected waves remain unchanged. (2) The wavelength of both the diffracted and reflected waves decreases. (3) The frequency of the diffracted wave decreases while that of the reflected wave remains

unchanged. A. (1) only B. (2) only C. (3) only D. (1) and (3) only

23 When a wave passes obliquely from one medium to another, which of the following occurs?

A. Refraction B. Reflection C. Diffraction D. Interference


24 A sound wave encounters an object of size smaller than the wavelength of the sound. Which of the

following statements is correct? A. Most of the wave is reflected. B. None of the wave is reflected. C. Most of the wave bends around the object. D. The incident wave and the wave behind the object are 180° out of phase.

25

In a ripple tank, a student produces two circular water waves by using two sources X and Y which are in phase. P, Q and R are three points in the ripple tank as shown. If the wavelength of the waves is 0.5 cm, at which of the following points constructive interference occurs? (1) P (2) Q (3) R A. (1) only B. (2) only C. (1) and (2) only D. (1), (2) and (3)

26

In a ripple tank, a student produces two circular water waves by using two sources X and Y which are in phase. P, Q and R are three points in the ripple tank as shown. If the wavelength of the waves is 4 cm, at which of the following points constructive interference occurs? (1) P (2) Q (3) R A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only


27 A student attaches two dippers to the same source and uses them to generate an interference pattern

of water waves. How can he increase the number of nodal lines of the interference pattern? (1) Move the two dippers farther apart. (2) Increase the frequency of the dippers. (3) Increase the depth of water. A. (1) only B. (2) only C. (1) and (2) only D. (1), (2) and (3)

28 A student uses two dippers A and B to generate an interference pattern of water waves. The dippers

vibrate at the same frequency. However, when one of dipper is up, another one is down. If n represents a whole number, constructive interference will occur at point P if A. PA – PB = nλ

B. PA – PB =2λn

C. PA – PB = λ

+

21n

D. PA – PB = λ

+

21 n

29 Which of the following statements about wave is incorrect?

A. A water wave transfers energy. B. A water wave cannot change its direction of propagation after it is produced. C. A water wave travels at a constant speed when the depth of the water remains unchanged. D. A water wave is an example of transverse wave.

30 A vibrator of frequency 5 Hz produces water waves in a ripple tank. Which of the following is the

possible speed and wavelength of the wave? Wavelength (cm) Speed (cm s−1)

A. 5x x B. x 5x

C. x 51 x

D. x 2x


31 Which of the following diagrams is correct when the water waves travel from a deep region to a shallow region in a ripple tank? A.

B.

C.

D.

32 The wavelength of a water wave travelling from a deep region to a shallow region is reduced because (1) the frequency of the water wave decreases. (2) the speed of the water wave increases. (3) the speed of the water wave decreases. A. (1) only B. (3) only C. (1) and (2) only D. (1) and (3) only


33

The diagram shows two water waves which are generated by two coherent sources S1 and S2. The solid lines represent wave crests and the dashed lines represent wave troughs. Which point is at a position of destructive interference? A. A B. B C. C D. D

34 A hand-held stroboscope is used to freeze a water wave of speed 5 cm s−1. There are 3 slits on the

stroboscope and the wave appears to be stationary when the stroboscope rotates at a speed of 0.5, 1, 1.5 and 3 revolutions per second only. What is the frequency of the wave? A. 1.5 Hz B. 3 Hz C. 9 Hz D. 15 Hz

35 Which of the following settings in a ripple tank will produce the most prominent diffraction pattern of a

water wave of wavelength of 2 cm? A. The wave passes through an obstacle of length of 4 cm. B. The wave passes through an obstacle of length of 2 cm. C. The wave passes through a gap of 4 cm. D. The wave passes through a gap of 1 cm.


36

The diagram shows a circular water wave travelling towards a straight barrier in a ripple tank. Which of the following diagrams shows the correct reflected wave? A.

B.

C.

D.

37 In which of the following waves will interference occur? (1) Sound (2) Light (3) Water A. (1) only B. (2) only C. (1) and (3) only D. (1), (2) and (3)


38 The spreading of a wave into a region behind an obstacle is known as A. interference. B. diffraction. C. diffusion. D. dispersion.

39 A boy drops a small stone into a water pond. The wavelength and frequency of the water wave

generated are 25 cm and 2 Hz respectively. What is the speed of the wave? A. 50 m s−1

B. 25 m s−1 C. 2.5 m s−1 D. 0.5 m s−1

40 A water pulse travels through a boundary from a shallow region P to a deep region Q. Which of the

following is correct? Wavelength Frequency Speed

A. λP < λQ fP = fQ vp < vQ B. λP > λQ fP = fQ vp > vQ C. λP < λQ fP > fQ vp = vQ D. λP > λQ fP < fQ vp = vQ

41 When a water wave reaches a boundary from a deep region to a shallow region, it will be

A. reflected totally. B. transmitted totally. C. partly reflected and partly transmitted. D. neither reflected nor transmitted.

42 Two waves of same frequency and amplitude meet at a point where they are 180° out of phase. Which

of the following is incorrect? A. They superimpose, resulting in zero intensity. B. Their amplitudes subtract, resulting in zero amplitude. C. Destructive interference occurs. D. Their energy at that point disappear and thus the energy of the waves after interference is half

that of the original waves.

43 When two waves of same amplitude but slightly different frequencies are added, (1) they interfere constructively, the total intensity of the waves is four times the individual intensity. (2) they interfere destructively, the total intensity of the waves is zero. (3) the waves alternate between constructive and destructive interferences at a rate called the beat

frequency. A. (1) only B. (3) only C. (1) and (3) only D. (2) and (3) only


44 A vibrator in a ripple tank generates a wave of frequency of 6 Hz. The wavelength of the wave is 0.12

m and it is moving towards a straight barrier. What is the speed of the reflected wave? A. 0.72 m s−1 B. 50 m s−1 C. Larger than 0.72 m s−1 D. Larger than 50 m s−1

45 A vibrator is placed at the centre of an inclined ripple tank as shown.

How does the wavelength of the wave change when it is moving towards the two ends P and Q of the ripple tank? Towards P Towards Q A. Decrease Decrease B. Decrease Increase C. Increase Decrease D. No change No change


46 Two breakwaters are used in a harbour shelter, which of the following diagrams shows the wave passing through them? A

B

C

D

47 A typical microwave oven produces a microwave of frequency 10 GHz. What is its wavelength? A. 3.3 × 10−1 m B. 3.0 × 10−2 m C. 3.0 × 10−8 m D. 3.3 × 10−10 m

48 The term “coherence” relates to

A. the polarization state of two waves. B. the diffraction of two waves. C. the sources distance between two waves. D. the phase relationship between two waves.


49 Which of the following electromagnetic waves has the greatest wavelength? A. Microwave B. Ultraviolet C. Visible light D. X-ray

50 Which of the following nature of light can be demonstrated by Young’s double-slit experiment?

(1) Light is a wave. (2) Light is a particle. (3) Light is a transverse wave. A. (1) only B. (2) only C. (1) and (3) only D. (1), (2) and (3) only

51 Which of the following statements is correct?

A. Light requires a medium to propagate. B. Light is generated by a vibrating charge. C. Light cannot travel through solids. D. Light is a mechanical wave.

52 Light is a

A. mechanical wave. B. transverse wave. C. longitudinal wave. D. circular wave.

53

The table shows the different members of the electromagnet spectrum. Name A. A. Radio wave B. X-ray C. Gamma ray D. Microwave

54 Which of the following about the types of different waves is correct?

Sound Radio wave X-ray A. Longitudinal Longitudinal Transverse B. Longitudinal Transverse Transverse C. Transverse Longitudinal Transverse D. Transverse Longitudinal Longitudinal


55 Wave P travels faster in air but has a shorter wavelength than another wave Q. Which of the following is correct? P Q A. Ultraviolet Microwave B. Red light Sound C. Sound Radio wave D. Ultraviolet X-ray

56 Which of the following statements is / are correct?

(1) X-ray can change the genetic codes of cells because it can break the chemical bonds in organic matter.

(2) No interference pattern can be seen when two hot filaments are used as light sources. (3) A prism can be used to disperse a white light. A. (1) only B. (2) only C. (1) and (2) only D. (1), (2) and (3)

57

From the electromagnetic spectrum shown, compare the wavelength, frequency and speed of P and Q.

Wavelength Frequency Speed A. λP < λQ fP > fQ vp > vQ B. λP > λQ fP < fQ vp < vQ C. λP < λQ fP > fQ vp = vQ D. λP > λQ fP < fQ vp = vQ

58 A rainbow has different colours because of

A. the dispersion of light. B. the diffraction of light. C. the interference of light. D. the reflection of light.

59 A student is investigating the properties of X-ray, gamma ray, infrared, visible light and ultraviolet.

Which of the following the student can be concluded? A. They are all harmful to human body. B. They can all be seen by human eyes. C. They are all affected by electric field. D. They all travel in vacuum at a speed of 3 × 108 m s−1.


60 Which of the following is/are the use(s) of X-ray? (1) Security system in airport (2) Medical diagnose (3) Crystal structure study A. (1) only B. (2) only C. (1) and (2) only D. (1), (2) and (3)

61 Which of the following statements best explains why interference patterns are not usually observed

from two ordinary light bulbs? A. Diffraction effects predominate. B. The two sources are out of phase. C. The two sources are not coherent. D. The interference pattern is too small to observe.

62 When compare visible light and X-ray, which of the following is correct?

A. The wavelength of X-ray is smaller. B. The speed of X-ray is greater. C. The frequency of X-ray is smaller. D. Both of them can be used to detect weapons.

63 The coherent light sources emit light of

(1) the same frequency. (2) the same amplitude. (3) a constant phase difference. A. (1) only B. (2) only C. (1) and (3) only D. (1), (2) and (3)

64 In a Young’s double-slit experiment, green light is used as the source. The interference fringes are

observed on a screen. Which one of the following can make the fringes to spread more loosely? A. Replace the green light by a blue light. B. Replace the green light by a red light. C. Move the screen closer to the slits. D. Move the light source closer to the slits.

65 Which of the following statements about the wavelength of an electromagnetic wave in a vacuum is

correct? A. The wavelengths of all the electromagnetic waves are the same. B. The wavelength is inversely proportional to the speed of the wave. C. The wavelength is inversely proportional to the frequency of the wave. D. The wavelength is directly proportional to the frequency of the wave.


66 Which of the following is probably the frequency of a green light?

A. 6.0 × 1014 Hz B. 3.0 × 107 Hz C. 1.5 × 102 Hz D. 6.0 × 10−6 Hz

67 Which of the following light would produce an interference pattern with the largest separation between

the bright fringes? A. Red B. Orange C. Green D. Blue

68 Which of the following electromagnetic waves cannot be detected by photographic films?

A. Infrared B. Microwave C. X-ray D. Gamma ray

69 The frequency of X-ray is 3 × 1017 Hz. What is its wavelength?

A. 10 µm B. 1 µm C. 1 nm D. 10 nm

70 A laser pulse was sent out from the earth and after 4.5 × 10−2 s, it is reflected back from a satellite in

space. What is the distance between the earth and the satellite? A. 4.5 × 106 m B. 6.75 × 106 m C. 9.0 × 106 m D. 13.5 × 106 m

71 Which of the following objects emit(s) infrared?

(1) A human body (2) A wooden block (3) An ice cube A. (1) only B. (2) only C. (1) and (2) only D. (1), (2) and (3)


72 Which of the following electromagnetic wave can be used for cooking? A. Radio wave B. Infrared C. X-ray D. Gamma ray

73 Find the critical angle of a diamond. Given that the refractive index for diamond is 2.42.

A. 0.042° B. 0.43° C. 23.68° D. 24.4°

74 If the critical angle of a material is 30°, find its refractive index.

A. 0.3 B. 0.5 C. 1.2 D. 2

75 We know that light travels in straight lines. However, inside a dark room, a little amount of light can still

be seen near a window. This is because A. the diffraction of light. B. the diffusion of light. C. the total internal reflection of light. D. the reflection of light.

76 The fuzzy edge of a shadow can best be explained by

A. diffuse reflection. B. total internal reflection. C. refraction. D. diffraction.

77 A tin foil is crumpled by a boy. Why the surface of the crumpled foil is not as shiny as before?

A. Because light is refracted after striking the surface. B. Because light is bent after striking the surface. C. Because light is scattered in different directions after striking the surface. D. Because light is absorbed by the tin foil.


78 The diagram shows the positions of four students in front of a plane mirror and their respective images.

Who can Amy see? (1) Bill (2) Carmen (3) David A. (1) only B. (1) and (2) only C. (2) and (3) only D. (1), (2) and (3)

79

Total internal reflection occurs in a prism as shown in the figure. Which of the following is the possible range of the refractive index, n, of the prism?

A. 12

1<< n

B. 22

1<< n

C. 21 << n D. n<2

80 When a man stands in front of a mirror, he can see his whole image. Which of the following is / are

true? (1) The length of the mirror is half the height of the man. (2) Diffuse reflection occurs. (3) Total internal reflection occurs. A. (1) only B. (3) only C. (1) and (2) only D. (2) and (3) only


81 Which of the following makes use of total internal reflection? (1) Telecommunications (2) Binoculars (3) Green house effect A. (1) only B. (3) only C. (1) and (2) only D. (1), (2) and (3) only

82 Since the critical angle of water is 48.8°, a fish beneath the water sees a normally 180°

horizon-to-horizon view above the water will subtend within an angle of A. 24.4°. B. 48.8°. C. 97.6°. D. 180°.

83 Which of the following is / are luminous object(s)?

(1) A light bulb (2) The moon (3) The human body A. (1) only B. (3) only C. (1) and (2) only D. (2) and (3) only

84 What happen to light rays when they hit an uneven surface from the same direction?

A. They are all reflected in the same direction. B. They are reflected in many directions. C. They are absorbed by the surface. D. They all pass through the surface and are diffracted.

85

When parallel rays of light are incident on an irregular surface as shown in the figure, which phenomenon of light occurs? A. Refraction B. Diffraction C. Regular reflection D. Diffuse reflection


86 The figure shows a light ray moving towards a smooth surface. Which arrow represents the possible direction of light ray after reflection?

A.

B.

C.

D.

87 Which of the following is / are correct? (1) The image formed by diffuse reflection is blurred, as the angle of reflection is greater than the

angle of incidence. (2) Diffuse reflection also occurs at a perfectly smooth surface. (3) Both regular and diffuse reflections obey the laws of reflection. A. (1) only B. (3) only C. (1) and (2) only D. (2) and (3) only

88 If a student stands 3 m in front of a mirror, what is the distance between he and his image?

A. 1.5 m B. 3 m C. 6 m D. 7.5 m

89 The figure shows a light ray passing from medium X into air.

What is the refractive index of medium X? A. 0.45 B. 0.68 C. 1.88 D. 2.24


90 What happens to a light beam when it passes through a translucent material such as waxed paper?

A. Most of the light passes through. B. Light is reflected in its incident path. C. Most of the light is absorbed and very little is reflected. D. Light is not allowed to pass through.

91 The apparent bending of a pencil in a glass of clear water is caused by

A. the reflection of light. B. the diffraction of light. C. the dispersion of light. D. the refraction of light.

92 Which of the following figures shows how light rays enable us to see a near object correctly?

A.

B.

C.

D.

93 Which of the following about an image formed by the reflection of light on a plane mirror is incorrect? A. The image is not real. B. The image is the same size as the object. C. The image is vertically inverted. D. The left side of the image is the right side of the object.


94

A light ray from the ray box is incident on a plane mirror as shown in the figure. Which of the following is / are correct? (1) The image is formed at P and is virtual. (2) The image is formed at Q and is real. (3) The light ray at Q appears to come from point P. A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only

95 Which of the following is / are an example of a light reflector?

(1) Fluorescent light (2) A mirror (3) The moon A. (1) only B. (3) only C. (1) and (2) only D. (2) and (3) only

96 If a child walks towards a mirror at a rate of 0.2 m s−1, at what speed will the child and his image

approach each other? A. 0.1 m s−1 B. 0.2 m s−1 C. 0.4 m s−1 D. 0.5 m s−1

97

In the figure shown, a monochromatic light ray is passing from medium A to medium B. Which of the following is the possible material for media A and B? Medium A Medium B A. Glass Alcohol B. Glass Diamond C. Alcohol Diamond D. Water Perspex


98 A light ray travels from a perpex plate into air. We know that the refractive index of the perpex plate is 1.47. Which of the following pairs is the possible values of the angle of incidence (i) and the angle of refraction (r)? i r A. 80.0° 53.3° B. 20.0° 50.0° C. 47.4° 30.0° D. 36.0° 60.0°

99 A monochromatic light ray A and a polychromatic light ray B (light with different frequencies) are both

incident on an air-glass interface. Which phenomenon could occur with ray B, but not with ray A? A. Refraction B. Reflection C. Dispersion D. Diffraction

100 A light ray travels through from a glass block to air. The angle of incidence is 20.0° while the angle of

refraction is 34.1°. Find the refractive index of the glass. A. 0.58 B. 0.61 C. 1.64 D. 1.70

101 Which of the following statement(s) concerning a convex lens is / are correct?

(1) It can form a real image. (2) It must be spherical. (3) The image is always inverted. A. (1) only B. (3) only C. (1) and (2) only D. (2) and (3) only

102 An artist writes some Chinese words on a piece of rice. He uses a magnifying glass to see his work as

shown in the diagram. f is the focal length of the lens. Where should he place the rice?

A. Q B. R C. S D. T


103 John places his spectacles above a physics textbook. As he raises the spectacles, the image of the

print on the textbook he sees remains erect while gradually decreasing in size. He concludes that his spectacles are A. plane glass. B. converging lenses. C. diverging lenses. D. a combination of converging and diverging lenses.

104 The advantage of a lens in a camera over a pinhole is to provide

(1) a greater light-gathering power. (2) a fixed focal length. (3) a lower cost. A. (1) only B. (3) only C. (1) and (2) only D. (1), (2) and (3)

105 We can see things in the world because there is a converging lens system in our eyes. What is / are

the nature of image formed on our retina when we are looking at a distant object? (1) Real (2) Erect (3) Diminished A. (1) only B. (2) only C. (1) and (2) only D. (1) and (3) only

106 Two red lights are passing through a convex lens as shown. They focal at the distance (d) from the

lens.

If two blue lights were used instead, what is the distance (db) they focal from the lens?

A. db < d B. d < db < 2d C. 2d < db D. db = d


107 A teacher uses an overhead projector for showing slides in a classroom, but students complained that the image is too small. The teacher then enlarged the image by moving the projector away from the screen, but the image becomes blurred. The image would get clear again by A. moving the lens closer to the slide. B. moving the lens farther from the slide. C. decreasing the amount of light in the room. D. increasing the power of the projector lamp.

108 Amy has long-sightedness and needs to wear a correction lens for making light rays

A. converge before they enter her eyes. B. diverge before they enter her eyes. C. converge after they enter her eyes. D. diverge after they enter her eyes.

109 Microscope is used to magnify the structure of the mosquito that causes the mosquito-borne diseases

recently. Which of the following components is utilized in a microscope? A. A plane mirror B. A concave lens C. A convex lens D. None of the above

110 In the diagram shown, which point is the principal focus of the lens?

A. P B. Q C. R D. S

111 A lens forms a real image three times the size of the object when the image is 0.12 m from the lens.

How far from the lens is the object? A. 0.36 m B. 0.09 m C. 0.04 m D. 0.03 m


112 Which of the following ray diagrams is incorrect? A.

B.

C.

D.

113

The diagram shows an object placed 10 cm away from a converging lens which has a focal length of 5 cm. At which point will the image be formed?

A. F2 B. Between O and F2

C. Between F2 and Q D. Q


114 If an object is placed at 2f from a converging lens of focal length f, the image will be (1) real. (2) inverted. (3) diminished. A. (1) only B. (3) only C. (1) and (2) only D. (1), (2) and (3)

115 John stands in front of a large converging lens in a theme park as shown. f is the focal length of the

lens. Which position will the image be formed?

A. P B. R C. S D. T

116 Which of the following statements is a characteristic of diverging lens?

A. The magnification of the image formed is less than 1. B. The image formed is real. C. The image formed is inverted. D. The image can be formed on a screen.

117 In which of the following optical device(s) will the size of the image formed always be smaller than the

size the object? (1) A plane mirror (2) A convex lens (3) A concave lens A. (1) only B. (3) only C. (1) and (2) only D. (2) and (3) only


118 Parallel light rays from the sun are incident on different shapes of glass. In which of the following shapes can a spot of white light be formed? A.

B.

C.

D.

119 The focal length of a lens does not depend on the A. material of the lens. B. shape of the lens. C. distance of an object from the lens. D. colour of the light incident on the lens.

120 A 1.2 m tall object is placed 2.0 m in front of a concave lens. The image is formed at 1.0 m from the

lens. What is the size of the image formed? A. 2.4 m B. 1.2 m C. 0.6 m D. 0.3 m

121 A convex lens of focal length f is used to produce an image of an object. If the image is required to form

at the same position as the object, how far from the lens should the object be placed?

A. 4f

B. 2f

C. f D. A convex lens cannot produce an image at the same position as the object.


122 A spherical lens is used to produce an image of an object on a screen. If the edge of the lens is covered with a plastic as shown, what will happen to the image formed?

A. The inner portion of the image disappears. B. The outer portion of the image disappears. C. The image becomes brighter. D. The image becomes dimmer.

123 The type of lens that spreads parallel light is a

(1) concave lens. (2) convex lens. (3) combination of convex and concave lenses of same focal length. A. (1) only B. (2) only C. (1) and (3) only D. (2) and (3) only

124 Two light rays from the same point of an object are refracted by a lens. A real image is formed when

the light rays A. pass through a concave lens. B. converge to a point. C. travel in parallel lines. D. diverge and appear to come from a point.

125

The experiment as shown is used to determine the focal length of the lens. Which of the following is equal to the focal length of the lens? A. P B. Q C. R D. P + Q


126 A concave lens has a focal length f. How far should an object be placed to obtain a real image? A. f B. 2f C. At infinity D. No real image can be formed.

127 A person suffering from short-sightedness has

A. an eye that is too long and needs a convex lens to focus distant objects. B. an eye that is too long and needs a concave lens to focus distant objects. C. an eye that is too short and needs a convex lens to focus near objects. D. an eye that is too short and needs a concave lens to focus near objects.

128 When a sound wave propagates through a reflective object of size comparable to the wavelength of

the sound, A. most of the wave is diffracted. B. most of the wave is refracted. C. most of the wave is reflected. D. none of the wave is diffracted.

129 What is the intensity level of a sound with intensity of 1.5 × 10−6 W m−2? (Given that I0 = 10−12 W m−2.)

A. 60.0 dB B. 61.8 dB C. 90.0 dB D. 150.0 dB

130 A violin string is made to vibrate by a bow to produce a note. How to lower the pitch of the note?

A. Decrease the amplitude of vibration of the string. B. Increase the amplitude of vibration of the string. C. Decrease the frequency of vibration of the string. D. Increase the frequency of vibration of the string.

131 The loudness of a sound wave is determined by

A. its amplitude. B. its frequency. C. its wavelength. D. the medium of the propagation of the sound.

132 The pitch of note X is lower than that of note Y and the frequency of note X is 256 Hz. Which of the

following is the most suitable frequency of note Y? A. 128 Hz B. 250 Hz C. 256 Hz D. 640 Hz


133 Which of the following is an evidence that sound can travel in water? A. Fishmen use light to attract fish into a fishing net. B. The fish in the sea is scared by the conservation of human on the shore and thus swims away. C. People on the shore can hear the sound of the flow of water in a river. D. People far away from the shore can hear the sound when the water is strike on a rock.

134 The sound from a small speaker is louder if the speaker is mounted on a hole in a larger wooden board.

Which of the following statements about this setting is correct? A. It allows the cone of the speaker move with a greater amplitude. B. It prevents sound from the back of the speaker interfere with sound from the front. C. It prevents sound from the back of the speaker superimpose with that from the front, causing

twice the intensity. D. The rim of the speaker transmits oscillations to the wooden board.

135 Two loudspeakers are placed side by side and driven by the same source at a frequency of 400 Hz.

John is sitting in front of and in the middle position between the speakers. Therefore, constructive interference occurs at the John’s position. If one of the speakers is gradually moved towards John, what is the minimum distance the speaker should move in order for John to experience the effect of constructive interference again? Given that the speed of sound is 340 m s−1. A. 0.85 m B. 1.18 m C. 1.70 m D. 1.76 m

136 In a mini-concert of a rock band, a 120 dB sound intensity level is detected in the position of the front

row. In a room, if a speaker produces a sound of 100 dB intensity level, how many speakers would be needed to produce the same intensity level as that in the front row of the concert? A. 10 B. 20 C. 100 D. 200

137 The intensity level of the "buzz" of a mosquito is 30 dB while that of the MTR train is 90 dB. Find the

ratio of the intensities of the sounds from the mosquito and the MTR train. A. 3 B. 60 C. 6 000 D. 106

138 A train whistle has an acoustic power output of 100 W. If the sound energy spreads out spherically,

what is the intensity level in dB at a distance of 100 m from the train? (Given that I0 = 10−12 W m−2.) A. 55 dB B. 89 dB C. 95 dB D. 120 dB


139 The frequency of a sound wave is determined by

A. the speed of the wave. B. the source of the wave. C. the medium of the wave. D. the loudness of the wave.

140 Bees which are not carrying honey fly with a flapping frequency of 440 Hz while those which are

carrying honey fly with a flapping frequency of 300 Hz. The sound made by bees which are not carrying honey has A. a lower pitch. B. a higher pitch. C. a smaller loudness. D. a greater loudness.

141 In an experiment, an electric bell is hung in a vacuum flask. This experiment shows that

A. the electric current passing through the bell gets weaker as air is pumped out. B. sound waves require a medium for propagation. C. our ears are insensitive to sound in vacuum. D. the clapper of the bell moves slower to hit the bell in vacuum, producing a very weak sound.

142 The frequency of a sound wave in air is 17 Hz and its speed is 340 m s−1. What is the wavelength of the

sound wave? A. 20 m B. 17.6 m C. 0.85 m D. 0.05 m

143 Which of the following statements about sound waves is correct?

A. The travel of sound waves is not affected by the medium through which it travels. B. Sound waves travel faster in air than in liquid. C. Sound waves travel faster in solid than in air. D. Sound waves cannot travel through a solid.

144 Which of the following is not a mechanical wave?

A. Sound wave B. Radio wave C. Wave in spring D. Water wave in the deep ocean

145 Which of the following statements about sound wave is not correct?

A. It is produced by the vibrations of particles. B. It can travel through a medium. E. It is not a mechanical wave. F. It can be diffracted.


146 What is the approximate range of audible frequencies for a human ear?

A. 20 Hz – 20 kHz B. 20 kHz – 200 kHz C. 200 kHz – 2 000 kHz D. 2000 kHz – 20 000 kHz

147 Sound wave is different from light wave because sound wave

A. is produced by an oscillating object. B. undergoes reflection. C. needs to propagate in a medium. D. exists with a variety of frequencies but light wave has a single frequency only.

148 The regions of compressions and rarefactions of a sound wave are established because

A. the sound wave undergoes diffraction behind obstacles. B. the reflected sound wave at the fixed end interferes with the incident wave. C. the speed of the sound wave changes as it travels through a medium. D. the longitudinal movement of air molecules produces pressure fluctuations.

149 Which of the following is different from others?

A. Sound wave B. Radio wave

C. Visible light D. Ultraviolet radiation

150 Why does the speed of sound depend on the temperature of the medium through which the sound travels? A. The human ear is more sensitive to sound at higher temperature. B. Wavelength is longer at higher temperature. C. As temperature increases, particles in the medium collide more often. D. As temperature decreases, particles in the medium are more loosely packed.

151 Which of the following determines the velocity of sound in air?

(1) Wavelength of the sound (2) Frequency of the sound (3) Temperature of the air A. (1) only B. (3) only C. (1) and (3) only D. (2) and (3) only

152 Which of the following statements about sound wave is / are correct?

(1) It conducts faster in solid than in gas. (2) It can be used to detect the depth of the sea. (3) If a hammer is strike on a long iron rod, a person at the other side of the rod can hear the sound

two times because of the echo. A. (1) only B. (3) only C. (1) and (2) only D. (1), (2) and (3)

153 The frequency of a sound in a 8 m long metal rod is 250 Hz. There are two completed sound waves in

the rod. The speed of sound in this metal is A. 250 m s−1. B. 500 m s−1. C. 750 m s−1. D. 1 000 m s−1.

End (03)Waves Revision MC Test.doc 35

(03)waves revision mc test

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