Waves_P1 [84 marks]

1. A sound wave has a wavelength of 0.20 m. What is the phase difference between two points along the wave which are 0.85 mapart?

A. zero

B. 45°

C. 90°

D. 180°

2. What is the phase difference, in rad, between the centre of a compression and the centre of a rarefaction for a longitudinal travellingwave?

A. 0

B.

C.

D.

π

2

π

2π

3. What statement about X-rays and ultraviolet radiation is correct?

A. X-rays travel faster in a vacuum than ultraviolet waves.

B. X-rays have a higher frequency than ultraviolet waves.

C. X-rays cannot be diffracted unlike ultraviolet waves.

D. Microwaves lie between X-rays and ultraviolet in the electromagnetic spectrum.

4. Two pulses are travelling towards each other.

What is a possible pulse shape when the pulses overlap?

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5. A girl in a stationary boat observes that 10 wave crests pass the boat every minute. What is the period of the water waves?

A. min

B. min

C. 10 min

D. 10 min

110

110

–1

–1

6. The graph shows the variation with distance x of the displacement of the particles of a medium in which a longitudinal wave istravelling from left to right. Displacements to the right of equilibrium positions are positive.

Which point is at the centre of a compression?

A. x = 0

B. x = 1 m

C. x = 2 m

D. x = 3 m

7. A travelling wave of period 5.0 ms travels along a stretched string at a speed of 40 m s . Two points on the string are 0.050 mapart.

What is the phase difference between the two points?

A. 0

B.

C.

D. 2

–1

π

2

π

π

8. A student stands a distance L from a wall and claps her hands. Immediately on hearing the reflection from the wall she claps herhands again. She continues to do this, so that successive claps and the sound of reflected claps coincide. The frequency at whichshe claps her hands is f. What is the speed of sound in air?

A.

B.

C. Lf

D. 2Lf

L

2f

L

f

9. A transverse travelling wave has an amplitude and wavelength . What is the minimum distance between a crest and a troughmeasured in the direction of energy propagation?

A.

B.

C.

D.

x0 λ

2x0

x0

λ

λ

2

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10. A wave on a string travels to the right as shown. The frequency of the wave is . At time , a small marker on the string is in theposition shown.

What is the position of the marker at ?

f t = 0

t = 14f

11. A wave pulse is sent along a light string which is attached to a heavy rope as shown. The diagrams are not to scale.

Which diagram shows the shape of the string and the rope after a short time?

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12. A wave of period 5.0m s travels through a medium. The graph shows the variation with distance d of the displacement x of points inthe medium.

What is the average speed of a point in the medium during one full oscillation?

A. 0m sB. 4.0m sC. 16m sD. 400m s

–1

–1

–1

–1

13. The diagram shows, at a particular instant in time, part of a rope along which a wave is travelling.

The wave is travelling from left to right.

Which arrow shows the direction of motion of the rope at the point shown?

A. W

B. X

C. Y

D. Z

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14. Which of the following correctly relates the direction of oscillation of the particles in a medium to the direction of energy propagationfor transverse and longitudinal waves?

15. Which of the following correctly describes the direction of a ray drawn relative to a wavefront for longitudinal and transverse waves?

16. Gas particles are equally spaced along a straight line. A sound wave passes through the gas. The positions of the gas particles atone instant are shown below.

Which of the distances shown is equal to the wavelength of the wave?

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17. Unpolarized light of intensity I is transmitted through a polarizer which has a transmission axis at an angle θ to the vertical. Thelight is then incident on a second polarizer with a transmission axis at an angle ϕ to the transmission axis of the first polarizer, asshown below.

The intensity of the light that emerges from the second polarizer is I. What is the ratio ?

A. 0.25

B. 0.5 cos (θ+φ)

C. 0.5 cos φD. cos θ cos φ

0

I

I0

2

2

2 2

18. What region of the electromagnetic spectrum includes waves of wavelength 5 ×10 m?

A. X-ray

B. Ultraviolet

C. Infrared

D. Microwave

–8

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19. A wave pulse is travelling along a dense thick rope which is connected to a less dense thin rope.

Which of the following is correct regarding the reflected and transmitted wave pulses after the wave pulse reaches the connection of the tworopes?

20. Which of the following gives regions of the electromagnetic spectrum in the order of decreasing frequency?

A. gamma-ray, microwave, visibleB. radio wave, infrared, microwaveC. ultraviolet, infrared, microwaveD. visible, gamma-ray, radio wave

21. Which of the following gives regions of the electromagnetic spectrum in the order of decreasing frequency?

A. gamma-ray, microwave, visibleB. radio wave, infrared, microwaveC. ultraviolet, infrared, microwaveD. visible, gamma-ray, radio wave

22. A transverse wave travels from left to right. The diagram below shows how, at a particular instant of time, the displacement ofparticles in the medium varies with position. Which arrow represents the direction of the velocity of the particle marked P?

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23. Which of the following electromagnetic waves has a frequency greater than that of visible light?

A. UltravioletB. RadioC. MicrowavesD. Infrared

24. One end of a horizontal string is fixed to a wall. A transverse pulse moves along the string as shown.

Which of the following statements are correct for the reflected pulse compared to the forward pulse?

I. It moves more slowly.

II. It has less energy.

III. It is inverted.

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

25. Which of the following is a value of wavelength that is found in the visible region of the electromagnetic spectrum?

A.

B.

C.

D.

4 × 10−5 m

4 × 10−7 m

4 × 10−9 m

4 × 10−11 m

26.

Diagram 1 represents equally spaced beads on a spring. The beads are 1 cm apart.

Diagram 1

A longitudinal wave propagates along the spring. Diagram 2 shows the position of the beads at a particular instant.

Diagram 2

Which of the following is the best estimate of the wavelength?

A. 2 cm

B. 4 cm

C. 8 cm

D. 16 cm

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27. Which of the following is the best estimate of the amplitude?

A. 0.4 cm

B. 0.8 cm

C. 1.6 cm

D. 3.2 cm

28. In which of the following regions of the electromagnetic spectrum is radiation of wavelength 600 nm located?

A. microwaves

B. radio waves

C. visible light

D. X-rays

29. Two wave pulses, each of amplitude A, approach each other. They then superpose before continuing in their original directions.What is the total amplitude during superposition and the amplitudes of the individual pulses after superposition?

30. Unpolarized light of intensity I is incident on the first of two polarizing sheets. Initially the planes of polarization of the sheets areperpendicular.

Which sheet must be rotated and by what angle so that light of intensity can emerge from the second sheet?

0

I0

4

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31. A beam of unpolarized light is incident on the first of two parallel polarizers. The transmission axes of the two polarizers are initiallyparallel.

The first polarizer is now rotated about the direction of the incident beam by an angle smaller than 90°. Which gives the changes, if any, inthe intensity and polarization of the transmitted light?

32. Properties of waves are

I. polarizationII. diffractionIII. refraction

Which of these properties apply to sound waves?

A. I and IIB. I and IIIC. II and IIID. I, II and III

33. A point source of light of amplitude A gives rise to a particular light intensity when viewed at a distance from the source. When theamplitude is increased and the viewing distance is doubled, the light intensity is doubled. What is the new amplitude of the source?

A. 2A

B. 2 A

C. 4A

D. 8A

0

0

√2 0

0

0

34. A point source emits sound waves of amplitude A. The sound intensity at a distance d from the source is I. What is the soundintensity at a distance 0.5d from the source when the source emits waves of amplitude 2A?

A. 16I

B. 4I

C. I

D. I14

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35. A water wave moves on the surface of a lake. P and Q are two points on the water surface. The wave is traveling towards the right.

The diagram shows the wave at time t = 0. Which graph shows how the displacements of P and Q vary with t?

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36. Horizontally polarized light of intensity I enters a polarizer P whose polarization axis makes an angle of θ degrees with thehorizontal. Light from P is then incident on a polarizer A with fixed vertical polarization axis.

The angle θ is varied from 0 to 90 degrees. Which of the following represents the variation with θ of the intensity I of the light transmittedthrough A?

0

37. Electromagnetic waves

A. always obey an inverse square law.

B. are made up of electric and magnetic fields of constant amplitude.

C. always travel at the same speed in a vacuum.

D. are always polarized.

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38. A wave pulse travels along a light string which is attached to a frictionless ring. The ring can move freely up and down a vertical rod.

What is the shape of the wave pulse after reflection?

39. Electromagnetic waves pass through a slit in a metal plate with minimal diffraction. The slit has a width of 0.25 m. What is thewavelength of the waves?

A. Much less than 0.25 m

B. Between 0.10 m and 0.40 m

C. Equal to 0.25 m

D. Much greater than 0.25 m

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40. Which graph shows the variation with amplitude A of the intensity I for a wave?

41. Wave generators placed at position P and position Q produce water waves of wavelength 4.0 cm. Each generator, operating alone,produces a wave oscillating with amplitude A at position R. Distances PR and QR are shown in the diagram below.

Both wave generators now operate together in phase. What is the amplitude of the oscillation of the resulting wave at R?

A. 0

B. A

C. A

D. 2A

2

42. Two wave pulses move towards each other as shown in the diagram.

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Which diagram shows a possible combination of the two pulses after a short time?

43. Wave generators placed at position P and position Q produce water waves of wavelength 4.0 cm. Each generator, operating alone,produces a wave oscillating with amplitude A at position R. Distances PR and QR are shown in the diagram below.

Both wave generators now operate together in phase. What is the amplitude of the oscillation of the resulting wave at R?A. 0B. AC. AD. 2A

2

44. An unpolarized ray of light in air is incident on the surface of water. The reflected ray is completely polarized. Which of the followingare separated by an angle of 90˚?

A. The incident ray and the reflected ray

B. The reflected ray and the refracted ray

C. The refracted ray and the incident ray

D. The refracted ray and the surface of the water

45. Two polarizers have polarizing axes that make an angle of 30˚ to each other. Unpolarized light of intensity I is incident on the firstpolarizer so that light of intensity I emerges from the second polarizer, as shown below.

The cosine of 30˚ is . What is the ratio ?

1.

2.

3.

4.

1

2

√3

2

I1

I2

38434

√383

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46. Unpolarized light of intensity is incident on a polarizer that has a vertical transmission axis.

The polarizer is rotated by an angle θ about the direction of the incident light. The intensity of the transmitted light is . Which graph correctly

shows the variation with the angle θ of the ratio ?

I0

II

I0

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47. A person wearing polarizing sunglasses stands at the edge of a pond in bright sunlight.

The surface of the pond is flat and the line of sight of the person makes an angle θ with the surface. The refractive index of the pond water isn. What is the value of θ for which the intensity of the sunlight reflected by the surface to the person’s eye is a minimum?

A. tan (n)

B. cos

C. cos (n)

D. tan

−1

−1 ( )1n

−1

−1 ( )1n

48. Two polarizing filters are set up so the transmitted light is at a maximum intensity.

Through which angle should polarizer 2 be rotated so that no light is transmitted?

A. 45ºB. 60ºC. 90ºD. 180º

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49. A point source of sound is placed behind a soundproof barrier as shown in the diagram.

From where Euan is standing he can hear the sound. Which of the following best explains this observation?

A. DiffractionB. InterferenceC. PolarizationD. Refraction

50. Unpolarized light of intensity I is incident on a polarizer with a vertical transmission axis. The transmitted light is incident on a sheet

of material X. After transmission through X the intensity of the light is .

It is suggested that X could be

I. a polarizer with vertical transmission axisII. a polarizer with horizontal transmission axisIII. non polarizing glass.

Which of the above suggestions is/are correct?

A. I and III onlyB. I onlyC. II onlyD. II and III only

0I0

2

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51. Waves emitted from sources X and Y have equal wavelengths and are initially in phase. The waves interfere destructively at point P,where the path difference is 0.60m.

What is a possible value for the wavelength of the waves?

A. 0.20 mB. 0.30 mC. 0.40 mD. 0.60 m

52. The intensity of radiation from a star at the surface of one of its planets is I. The distance between the star and the planet is d.

What is the intensity at the surface of another planet which is a distance from the star?

A. 4IB. 8IC. 16ID. 64I

d

4

53. Progressive (travelling) waves S and T have the same frequency and are in the same medium. S has amplitude 2.0 m and T hasamplitude 4.0 m. What is the ratio of the intensity of T to the intensity of S?

A.

B.

C. 2

D. 4

14

12

54. Unpolarized light is incident on the surface of a transparent medium. The reflected light is completely plane polarized. The refractedlight will be

A. unpolarized.B. partially plane polarized.C. completely plane polarized at right angles to the reflected light.D. completely plane polarized parallel to the reflected light.

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55. Two wave pulses travel along a string towards each other. The diagram shows their positions at a moment in time.

Which of the following shows a possible configuration of the pulses at a later time?

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56. A beam of unpolarized light is incident on the surface of a liquid and is partially reflected and partially refracted as shown below.

The reflected light is completely horizontally polarized. Which of the following is the refractive index of the liquid?

A. tan 40°

B. tan 50°

C.

D.

sin40∘

sin50∘

sin40∘

cos50∘

57. Unpolarized light is incident on a polarizer. The light transmitted by the first polarizer is then incident on a second polarizer. Thepolarizing axis of the second polarizer is at 60º to that of the first polarizer.

The intensity emerging from the second polarizer is I .

Which of the following correctly gives the intensity incident on the first polarizer?

A.

B.

C. 4I

D. 8I

f

If

8

If

4

f

f

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58. The diagram shows an interference pattern produced by two sources that oscillate on the surface of a liquid.

Which of the distances shown in the diagram corresponds to one fringe width of the interference pattern?

59. What are the changes in the speed and in the wavelength of monochromatic light when the light passes from water to air?

60. A pair of slits in a double slit experiment are illuminated with monochromatic light of wavelength 480 nm. The slits are separated by1.0 mm. What is the separation of the fringes when observed at a distance of 2.0 m from the slits?

A. 2.4 × 10 mm

B. 9.6 × 10 mm

C. 2.4 × 10 mm

D. 9.6 × 10 mm

–4

–4

–1

–1

61. A ray of light passes from the air into a long glass plate of refractive index n at an angle θ to the edge of the plate.

The ray is incident on the internal surface of the glass plate and the refracted ray travels along the external surface of the plate.

What change to n and what change to θ will cause the ray to travel entirely within the plate after incidence?

4

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62. The refractive index for light travelling from medium X to medium Y is . The refractive index for light travelling from medium Y to

medium Z is . What is the refractive index for light travelling from medium X to medium Z?

A.

B.

C.

D.

43

35

45

1512

54

2915

63. When a sound wave travels from a region of hot air to a region of cold air, it refracts as shown.

What changes occur in the frequency and wavelength of the sound as it passes from the hot air to the cold air?

64. A light ray is incident on an air–diamond boundary. The refractive index of diamond is greater than 1. Which diagram shows thecorrect path of the light ray?

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65. A spring XY lies on a frictionless table with the end Y free.

A horizontal pulse travels along the spring from X to Y. What happens when the pulse reaches Y?

A. The pulse will be reflected towards X and inverted. B. The pulse will be reflected towards X and not be inverted. C. Y will move and the pulse will disappear. D. Y will not move and the pulse will disappear.

66. Which diagram shows the shape of the wavefront as a result of the diffraction of plane waves by an object?

67. A light ray passes from air to water as shown.

What are the change in the wavelength of the light wave and the change in the angle the ray makes with the normal to the surface?

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68. Light is incident from air on the surface of a transparent medium.

When V is equal to the Brewster angle, which angle is equal to 90°?

A.

B. W only

C.

D. Z only

V + W

X + Y

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69. A water wave entering a harbour passes suddenly from deep to shallow water. In deep water, the wave has frequency ƒ and speedv . In shallow water, the wave has frequency ƒ and speed v .

Which of the following compares the frequencies and speeds of the wave between deep water and shallow water?

1

1 2 2

70. A high solid wall separates two gardens X and Y. Music from a loudspeaker in X can be heard in Y even though X cannot be seenfrom Y. The music can be heard in Y due to

A. absorption.

B. diffraction.

C. reflection.

D. refraction.

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71. The speed of a wave in medium X is greater than the speed of the wave in medium Y. Which diagram shows the correct refractionof the wavefronts at the boundary between X and Y?

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72. Two loudspeakers, L and L , emit identical sound waves.

The waves leaving L and L are in phase and are observed at points P and Q.

The wavelength of the sound is 0.60 m. The distances of points P and Q from the loudspeakers are shown in the diagram.

Which of the following is true about the intensity of the sound at P and the intensity of the sound at Q?

1 2

1 2

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73. Monochromatic coherent light is incident on a narrow rectangular slit. The diffracted light is observed on a distant screen. The graphbelow shows how the intensity of the light varies with position on the screen.

The width of the slit is reduced.

Which graph shows how the intensity of light observed varies with position on the screen? The original diffraction pattern is shown with adotted line.

74. Two identical waves of wavelength λ leave two sources in phase. The waves meet and superpose after travelling differentdistances. Which path difference will result in destructive interference?

A.

B.

C.

D. λ

λ

4

λ

2

3λ

4

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75. Light of wavelength 600 nm travels from air to glass at normal incidence. The refractive index of the glass is 1.5. The speed of lightin air is c. Which of the following correctly identifies the speed of the waves and their wavelength in the glass?

76. A ray of light travels from a vacuum into glass as shown below.

In glass, light has speed v. In a vacuum, light has speed c. Which of the following gives the refractive index of glass?

A.

B.

C.

D.

cv

vc

sinc

sinv

sinv

sinc

77. The phenomenon of diffraction is associated with

A. sound waves only.B. light waves only.C. water waves only.D. all waves.

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78. Light travels from air into glass as shown below.

What is the refractive index of glass?

A.

B.

C.

D.

sinP

sinS

sinQ

sinR

sinP

sinR

sinQ

sinS

79. Light travels from air into glass as shown below.

The refractive index of the glass is

A.

B.

C.

D.

sin30∘

sin80∘

sin80∘

sin30∘

sin60∘

sin10∘

sin10∘

sin60∘

80. Monochromatic light travels from air into water. Which of the following describes the changes in wavelength and speed?

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81. In two separate experiments monochromatic light is incident on a single slit. The diagrams show the diffraction patterns obtained ona screen far from the slit. In the top diagram the wavelength of light is and the slit width is . In the bottom diagram thewavelength of light is and the slit width is .

In each experiment the distance between the slit and the screen is the same. Which of the following may be deduced?

A.

B.

C.

D.

λ1 b1

λ2 b2

<λ1

b1

λ2

b2

>λ1

b1

λ2

b2

b1 < b2

λ1 > λ2

82. A ray of light is incident on a boundary between glass and air.

Which of the following is the refractive index of glass?

A.

B.

C.

D.

sinθ1

sinθ3

sinθ1

sinθ4

sinθ3

sinθ2

sinθ4

sinθ1

83. An orchestra playing on boat X can be heard by tourists on boat Y, which is situated out of sight of boat X around a headland.

The sound from X can be heard on Y due to

A. refraction.

B. reflection.

C. diffraction.

D. transmission.

84. What is the best estimate for the refractive index of a medium in which light travels at a speed of ?

A. 0.9

B. 1.0

C. 1.1

D. 2.7

2.7 × 108 ms−1

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