Physics Wave revision question

1. 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. (N – 1).

B. (N – 1).

C. (N).

D. (N).

(1)

2. 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.

D. 0.

(1)

3. 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.

(1)

4. A pulse is sent down a string fixed at one end.

Which one of the following diagrams best represents the reflected pulse?

(1)

5. 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?

(1)

6. 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?

(1)

7. 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 later?

(1)

8. 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

(1)

9. 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.

(1)

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

(1)

11. 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?

(1)

12. What change, if any, occurs in the wavelength and frequency of a light wave as it crosses a boundary from air into glass?

(1)

13. The variation with time t of the separate displacements d of a point in a medium due to two waves is 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?

(1)

14. 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.

(1)

15. 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.

(1)

16. 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.

(1)

17. 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

(1)

18. 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.

(1)

19. 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.

(1)

20. 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.

(1)

j Ð21. A wave travels from one medium to another. Which of the following is true about its frequency and wavelength?

(1)

22. 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.

(1)

23. 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?

(1)

24. 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. sin P = constant × sin R

B. sin P = constant × sin S

C. sin Q = constant × sin R

D. sin Q = constant × sin S

(1)

25. 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?

(1)

26. 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 later?

(1)

27. 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?

(1)

28. 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?

(1)

29. 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?

(1)

30. 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

(1)

31. Which of the ...

This is a preview of the whole essay

(1)

29. 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?

(1)

30. 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

(1)

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

(1)

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

(1)

33. Two bodies are brought into thermal contact with each other. No thermal energy transfer takes place between the bodies. It may be deduced therefore, that the bodies must have the same

A. specific heat capacity.

B. heat capacity.

C. temperature.

D. internal energy.

(1)

34. The phenomenon of diffraction is associated with

A. sound waves only.

B. light waves only.

C. water waves only.

D. all waves.

(1)

35. 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.

Which of the following diagrams is correct?

(1)

36. 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.

(1)

37. 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?

(1)

38. A transverse travelling wave has amplitude A0 and wavelength λ.

The distance between a crest and its neighbouring trough, measured in the direction of energy transfer of the wave is equal to

A. A0.

B. 2A0.

C. .

D. λ.

(1)

39. A light wave travelling through a vacuum is incident on a block of glass. What change, if any, occurs in the frequency and amplitude of the wave as it travels into the glass?

(1)

40. Light travelling from water to air is incident on a boundary.

Which of the following is a correct statement of Snell’s law for this situation?

A. sin Z = constant × sin Y

B. sin W = constant × sin Z

C. sin X = constant × sin Z

D. sin W = constant × sin Y

(1)

41. A pulse is travelling along a string attached to a wall.

Which of the following shows the shape of the string after reflection from the wall?

(1)

42. The diagram below shows the displacement-position graph at a particular instant for a longitudinal wave travelling along a spring.

A positive displacement on the graph indicates that the coils of the spring are displaced to the right of their equilibrium position.

At which position along the spring is the displacement of two adjacent coils a maximum?

A. A

B. B

C. C

D. D

(1)

43. The graph below shows the variation with time t of the displacement x of a particle undergoing simple harmonic motion.

Which graph correctly shows the variation with time t of the acceleration a of the particle?

(1)

44. A wooden block is at rest on a horizontal frictionless surface. A horizontal spring is attached between the block and a rigid support.

The block is displaced to the right by an amount X and is then released. The period of oscillations is T and the total energy of the system is E.

For an initial displacement of which of the following shows the best estimate for the period of oscillations and the total energy of the system?

(1)

45. Which of the following correctly describes the change, if any, in the speed, wavelength and frequency of a light wave as it passes from air into glass?

(1)

46. 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.

(1)

47. The graph below shows the variation with time t of the displacement x of a particle undergoing simple harmonic motion.

Which graph correctly shows the variation with time t of the acceleration a of the particle?

(1)

48. This question is about waves and wave properties.

(a) By making reference to waves, distinguish between a ray and a wavefront.

.....................................................................................................................................

(3)

The diagram below shows three wavefronts incident on a boundary between medium I and medium R. Wavefront CD is shown crossing the boundary. Wavefront EF is incomplete.

(b) (i) On the diagram above, draw a line to complete the wavefront EF.

(1)

(ii) Explain in which medium, I or R, the wave has the higher speed.

...........................................................................................................................

(3)

(iii) By taking appropriate measurements from the diagram, determine the ratio of the speeds of the wave travelling from medium I to medium R.

...........................................................................................................................

(2)

The graph below shows the variation with time t of the velocity v of one particle of the medium through which the wave is travelling.

...........................................................................................................................

(2)

(ii) Determine the frequency of oscillation of the particle.

...........................................................................................................................

(2)

(iii) Mark on the graph with the letter M one time at which the particle is at maximum displacement.

(1)

(iv) Estimate the area between the curve and the x-axis from the time t = 0 to the time t = 1.5 ms.

...........................................................................................................................

(2)

(v) Suggest what the area in c (iv) represents.

...........................................................................................................................

(1)

(Total 17 marks)

49. This question is about sound waves.

A sound wave of frequency 660 Hz passes through air. The variation of particle displacement with distance along the wave at one instant of time is shown below.

(a) State whether this wave is an example of a longitudinal or a transverse wave.

.....................................................................................................................................

(1)

(b) Using data from the above graph, deduce for this sound wave,

(i) the wavelength.

...........................................................................................................................

(1)

(ii) the amplitude.

...........................................................................................................................

(1)

(iii) the speed.

...........................................................................................................................

(2)

(Total 5 marks)

50. This question is about waves and wave motion.

(a) (i) Define what is meant by the speed of a wave.

...........................................................................................................................

(2)

(ii) Light is emitted from a candle flame. Explain why, in this situation, it is correct to refer to the “speed of the emitted light”, rather than its velocity.

...........................................................................................................................

(2)

(b) (i) Define, by reference to wave motion, what is meant by displacement.

...........................................................................................................................

(2)

(ii) By reference to displacement, describe the difference between a longitudinal wave and a transverse wave.

...........................................................................................................................

(3)

The centre of an earthquake produces both longitudinal waves (P waves) and transverse waves (S waves). The graph below shows the variation with time t of the distance d moved by the two types of wave.

(i) the P waves.

...........................................................................................................................

(1)

(ii) the S waves.

...........................................................................................................................

(1)

The waves from an earthquake close to the Earth’s surface are detected at three laboratories L1, L2 and L3. The laboratories are at the corners of a triangle so that each is separated from the others by a distance of 900 km, as shown in the diagram below.

The records of the variation with time of the vibrations produced by the earthquake as detected at the three laboratories are shown below. All three records were started at the same time.

On each record, one pulse is made by the S wave and the other by the P wave. The separation of the two pulses is referred to as the S-P interval.

(d) (i) On the trace produced by laboratory L2, identify, by reference to your answers in (c), the pulse due to the P wave (label the pulse P).

(1)

(ii) Using evidence from the records of the earthquake, state which laboratory was closest to the site of the earthquake.

...........................................................................................................................

(1)

(iii) State three separate pieces of evidence for your statement in (d)(ii).

(3)

1. .................................................................................................................

.................................................................................................................

2. .................................................................................................................

.................................................................................................................

3. .................................................................................................................

.................................................................................................................

(iv) The S-P intervals are 68 s, 42 s and 27 s for laboratories L1, L2 and L3 respectively. Use the graph, or otherwise, to determine the distance of the earthquake from each laboratory. Explain your working.

...........................................................................................................................

Distance from L1 = ......................km

...........................................................................................................................

Distance from L2 = ......................km

...........................................................................................................................

Distance from L3 = ......................km

...........................................................................................................................

(4)

(v) Mark on the diagram a possible site of the earthquake.

(1)

There is a tall building near to the site of the earthquake, as illustrated below.

The base of the building vibrates horizontally due to the earthquake.

(e) (i) On the diagram above, draw the fundamental mode of vibration of the building caused by these vibrations.

(1)

The building is of height 280 m and the mean speed of waves in the structure of the building is 3.4 × 103 ms–1.

(ii) Explain quantitatively why earthquake waves of frequency about 6 Hz are likely to be very destructive.

...........................................................................................................................

(3)

(Total 25 marks)

51. This question is about waves and wave motion.

(a) Describe, by reference to the propagation of energy, what is meant by a transverse wave.

Transverse wave

(2)

.....................................................................................................................................

(b) State one example, other than a wave on a string, of a transverse wave.

.....................................................................................................................................

(1)

A transverse wave is travelling along a string that is under tension. The diagram below shows the displacement of part of the string at time t = 0. The dotted line shows the position of the string when there is no wave travelling along it.

(i) the amplitude (label this A);

(1)

(ii) the wavelength (label this λ).

(1)

(d) The period of the wave is 1.2 × 10–3 s. Deduce that the speed of the wave is 250 m s–1.

.....................................................................................................................................

(2)

(e) Using the axes below, draw the displacement of the string when t = 3.0 × 10–4 s. (The displacement of the string at t = 0 is shown as a dotted line.)

(3)

(Total 10 marks)

52. This question is about waves.

(a) In the scale diagram below, plane wavefronts travel from medium 1 to medium 2 across the boundary AB.

State and explain in which medium the wavefronts have the greater speed.

...................................................................................................................................

(3)

(b) By taking measurements from the diagram, determine the ratio

...................................................................................................................................

(3)

(Total 6 marks)

53. Travelling waves

(a) Graph 1 below shows the variation with time t of the displacement d of a travelling (progressive) wave. Graph 2 shows the variation with distance x along the same wave of its displacement d.

(i) State what is meant by a travelling wave.

.........................................................................................................................

(1)

(ii) Use the graphs to determine the amplitude, wavelength, frequency and speed of the wave.

Amplitude: .................................................................................................

(1)

Wavelength: .................................................................................................

(1)

Frequency: .................................................................................................

.................................................................................................

(1)

Speed: .................................................................................................

.................................................................................................

(1)

Refraction of waves

(b) The diagram below shows plane wavefronts incident on a boundary between two media A and B.

The ratio

The angle between an incident wavefront and the normal to the boundary is 50°.

(i) Calculate the angle between a refracted wavefront and the normal to the boundary.

.........................................................................................................................

(3)

(ii) On the diagram above, construct three wavefronts to show the refraction of the wave at the boundary.

(3)

(Total 11 marks)

54. Waves on a string

A travelling wave is created on a string. The graph below shows the variation with time t of the displacement y of a particular point on the string.

The variation with distance x of the displacement y of the string at t = 0 is shown below.

(a) Use information from the graphs to calculate, for this wave,

(i) the wavelength;

.........................................................................................................................

(1)

(ii) the frequency;

.........................................................................................................................

(2)

(iii) the speed of the wave.

.........................................................................................................................

(1)

(b) The wave is moving from left to right and has period T.

(i) On graph 1, draw a labelled line to indicate the amplitude of the wave.

(1)

(ii) On graph 2, draw the displacement of the string at

(2)

(Total 7 marks)

55. Wave properties

(a) By reference to the energy of a travelling wave, state what is meant by

(i) a ray.

.........................................................................................................................

(1)

(ii) wave speed.

.........................................................................................................................

(1)

(b) The graph below shows the variation with time t of the displacement xA of wave A as it passes through a point P.

The graph below shows the variation with time t of the displacement xB of wave B as it passes through point P.

(i) Calculate the frequency of the waves.

.........................................................................................................................

(1)

(ii) The waves pass simultaneously through point P. Use the graphs to determine the resultant displacement at point P of the two waves at time t = 1.0 ms and at time t = 8.0 ms.

At t = 1.0 ms: ...............................................................................................

...............................................................................................

At t = 8.0 ms: ...............................................................................................

...............................................................................................

(3)

(Total 6 marks)

56. This question is about waves.

(a) With reference to the direction of energy transfer through a medium, distinguish between a transverse wave and a longitudinal wave.

......................................................................................................................................

(3)

(b) A wave is travelling along the surface of some shallow water in the x-direction. The graph shows the variation with time t of the displacement d of a particle of water.

Use the graph to determine for the wave

(i) the frequency,

...........................................................................................................................

(2)

(ii) the amplitude.

...........................................................................................................................

(1)

.....................................................................................................................................

(2)

(d) The graph in (b) shows the displacement of a particle at the position x = 0.

On the axes below, draw a graph to show the variation with distance x along the water surface of the displacement d of the water surface at time t = 0.070 s.

(3)

(e) The wave encounters a shelf that divides the water into two separate depths. The water to the right of the shelf is deeper than that to the left of the shelf.

The angle between the wavefronts in the shallow water and the shelf is 30°. The speed of the wave in the shallow water is 15 cm s–1 and in the deeper water is 20 cm s–1. For the wave in the deeper water, determine the angle between the normal to the wavefronts and the shelf.

.....................................................................................................................................

(3)

(Total 14 marks)

57. Simple harmonic motion and the greenhouse effect

(a) A body is displaced from equilibrium. State the two conditions necessary for the body to execute simple harmonic motion.

1. .........................................................................................................................

.........................................................................................................................

2. .........................................................................................................................

.........................................................................................................................

(2)

(b) In a simple model of a methane molecule, a hydrogen atom and the carbon atom can be regarded as two masses attached by a spring. A hydrogen atom is much less massive than the carbon atom such that any displacement of the carbon atom may be ignored.

The graph below shows the variation with time t of the displacement x from its equilibrium position of a hydrogen atom in a molecule of methane.

The mass of hydrogen atom is 1.7 × 10–27 kg. Use data from the graph above

(i) to determine its amplitude of oscillation.

.........................................................................................................................

(1)

(ii) to show that the frequency of its oscillation is 9.1 × 1013 Hz.

.........................................................................................................................

(2)

(iii) to show that the maximum kinetic energy of the hydrogen atom is 6.2 × 10–18 J.

.........................................................................................................................

(2)

(c) On the grid below, sketch a graph to show the variation with time t of the speed v of the hydrogen atom for one period of oscillation starting at t = 0. (There is no need to add values to the speed axis.)

(3)

(d) Assuming that the motion of the hydrogen atom is simple harmonic, its frequency of oscillation f is given by the expression

where k is the force per unit displacement between a hydrogen atom and the carbon atom and mp is the mass of a proton.

(i) Show that the value of k is approximately 560 N m–1.

.........................................................................................................................

(1)

(ii) Estimate, using your answer to (d)(i), the maximum acceleration of the hydrogen atom.

.........................................................................................................................

(2)

(e) Methane is classified as a greenhouse gas.

(i) Describe what is meant by a greenhouse gas.

.........................................................................................................................

(2)

(ii) Electromagnetic radiation of frequency 9.1 × 1013 Hz is in the infrared region of the electromagnetic spectrum. Suggest, based on the information given in (b)(ii), why methane is classified as a greenhouse gas.

.........................................................................................................................

(2)

(Total 17 marks)