(Total 1 mark) IB Questionbank Physics 1

Transcription

1 1. A transverse wave travels from left to right. The diagram below shows how, at a particular instant of time, the displacement of particles in the medium varies with position. Which arrow represents the direction of the velocity of the particle marked P? (Total 1 mark) IB Questionbank Physics 1

2 2. The graph shows how the displacement varies with time for an object undergoing simple harmonic motion. Which graph shows how the object s acceleration a varies with time t? (Total 1 mark) IB Questionbank Physics 2

3 3. Light travels from air into glass as shown below. What is the refractive index of glass? A. sin P sin S B. sin Q sin R C. sin P sin R D. sin Q sin S (Total 1 mark) IB Questionbank Physics 3

4 4. Which of the following electromagnetic waves has a frequency greater than that of visible light? A. Ultraviolet B. Radio C. Microwaves D. Infrared (Total 1 mark) 5. This question is about simple harmonic oscillations. A longitudinal wave travels through a medium from left to right. Graph 1 shows the variation with time t of the displacement x of a particle P in the medium. Graph 1 (a) For particle P, (i) state how graph 1 shows that its oscillations are not damped. IB Questionbank Physics 4

5 (ii) calculate the magnitude of its maximum acceleration. (2) (iii) calculate its speed at t = 0.12 s. (2) (iv) state its direction of motion at t = 0.12 s. IB Questionbank Physics 5

6 (b) Graph 2 shows the variation with position d of the displacement x of particles in the medium at a particular instant of time. Graph 2 Determine for the longitudinal wave, using graph 1 and graph 2, (i) the frequency. (2) (ii) the speed. (2) IB Questionbank Physics 6

7 Graph 2 reproduced to assist with answering (c)(i). (c) The diagram shows the equilibrium positions of six particles in the medium. (i) On the diagram above, draw crosses to indicate the positions of these six particles at the instant of time when the displacement is given by graph 2. (3) IB Questionbank Physics 7

8 (ii) On the diagram above, label with the letter C a particle that is at the centre of a compression. (Total 14 marks) 6. A particle oscillates with simple harmonic motion with period T. At time t = 0, the particle has its maximum displacement. Which graph shows the variation with time t of the kinetic energy E k of the particle? (Total 1 mark) IB Questionbank Physics 8

9 7. An object is undergoing simple harmonic motion with light damping. The natural frequency of oscillation of the object is f 0. A periodic force of frequency f is applied to the object. Which of the following graphs best shows how the amplitude a of oscillation of the object varies with f? (Total 1 mark) IB Questionbank Physics 9

10 8. The graph shows measurements of the height h of sea level at different times t in the Bay of Fundy. Which of the following gives the approximate amplitude and period of the tides? Amplitude Period A. 6.5 m 6 hours B. 13 m 12 hours C. 6.5 m 12 hours D. 13 m 6 hours (Total 1 mark) IB Questionbank Physics 10

11 λ 9. Two waves meet at a point. The waves have a path difference of. The phase difference 4 between the waves is π A. rad. 8 π B. rad. 4 π C. rad. 2 D. π rad. (Total 1 mark) 10. This question is about simple harmonic motion (SHM) and a wave in a string. (a) By reference to simple harmonic motion, state what is meant by amplitude (b) A liquid is contained in a U-tube. Diagram 1 Diagram 2 The pressure on the liquid in one side of the tube is increased so that the liquid is displaced as shown in diagram 2. When the pressure is suddenly released the liquid oscillates. The damping of the oscillations is small. IB Questionbank Physics 11

12 (i) Describe what is meant by damping. (2) (ii) The displacement of the liquid surface from its equilibrium position is x. The acceleration a of the liquid in the tube is given by the expression a = 2g l x where g is the acceleration of free fall and l is the total length of the liquid column. The total length of the liquid column in the tube is 0.32 m. Determine the period of oscillation. (3) IB Questionbank Physics 12

13 (c) A wave is travelling along a string. The string can be modelled as a single line of particles and each particle executes simple harmonic motion. The period of oscillation of the particles is 0.80 s. The graph shows the displacement y of part of the string at time t = 0. The distance along the string is d. (i) On the graph, draw an arrow to show the direction of motion of particle P at the point marked on the string. (ii) Determine the magnitude of the velocity of particle P. (4) IB Questionbank Physics 13

14 (iii) Show that the speed of the wave is 5.0 m s 1. (3) (iv) On the graph above, label with the letter X the position of particle P at t = 0.40 s. (Total 15 marks) 11. A string vibrates with fundamental frequency f. The wavelength of the sound produced in air is λ. Which of the following correctly gives the frequency of vibration of the fourth harmonic of the string and the wavelength of the sound in air? A. Frequency f 2 Wavelength λ 4 B. 4 f 4λ C. f 2 4λ D. 4 f λ 4 (Total 1 mark) 12. This question is about simple harmonic motion (SHM), wave motion and polarization. (a) By reference to simple harmonic motion, state what is meant by amplitude IB Questionbank Physics 14

15 (b) A liquid is contained in a U-tube. Diagram 1 Diagram 2 The pressure on the liquid in one side of the tube is increased so that the liquid is displaced as shown in diagram 2. When the pressure is suddenly released the liquid oscillates. The damping of the oscillations is small. (i) Describe what is meant by damping. (2) (ii) The displacement of the liquid surface from its equilibrium position is x. The acceleration a of the liquid in the tube is given by the expression a = 2g l x where g is the acceleration of free fall and l is the total length of the liquid column. Explain, with reference to the motion of the liquid, the significance of the minus sign. (2) IB Questionbank Physics 15

16 (iii) The total length of the liquid column in the tube is 0.32 m. Determine the period of oscillation. (3) (c) A wave is travelling along a string. The string can be modelled as a single line of particles and each particle executes simple harmonic motion. The period of oscillation of the particles is 0.80 s. The graph shows the displacement y of part of the string at time t = 0. The distance along the string is d. (i) On the graph, draw an arrow to show the direction of motion of particle P at the point marked on the string. IB Questionbank Physics 16

17 (ii) Determine the magnitude of the velocity of particle P. (4) (iii) Show that the speed of the wave is 5.0 m s 1. (3) (iv) On the graph above, label with the letter X the position of particle P at t = 0.40 s. IB Questionbank Physics 17

18 (d) The string in (c) is fixed at both ends and is made to vibrate in a vertical plane in its first harmonic. (i) Describe how the standing wave in the string gives rise to the first harmonic. (3) (ii) Outline how a travelling wave in a string can be used to describe the nature of polarized light. (3) IB Questionbank Physics 18

19 (e) James is wearing polarized sunglasses and views the sunlight reflected from the smooth surface of a lake. The angle θ is the angle between the surface of the lake and James s line of sight. Calculate the value of θ at which the reflected sunlight from the surface is minimized. The refractive index of the water is (2) (Total 25 marks) IB Questionbank Physics 19

20 13. The graph shows how the velocity v of an object undergoing simple harmonic motion varies with time t for one complete period of oscillation. Which of the following sketch graphs best shows how the total energy E of the object varies with t? (Total 1 mark) IB Questionbank Physics 20

21 14. A force that varies sinusoidally is applied to a system that is lightly damped. Which of the following must be true of the force for resonance to occur? A. It must always be in anti-phase with the oscillations of the system. B. Its direction must always be in the direction of motion of the oscillations of the system. C. Its frequency must be equal to the frequency of oscillation of the system. D. Its amplitude must be equal to the amplitude of oscillation of the system. (Total 1 mark) 15. Two waves meet at a point in space. Which of the following properties always add together? A. Displacement B. Amplitude C. Speed D. Frequency (Total 1 mark) 16. This question is about water wave motion. A small sphere, mounted at the end of a vertical rod, dips below the surface of shallow water in a tray. The sphere is driven vertically up and down by a motor attached to the rod. The oscillations of the sphere produce travelling waves on the surface of the water. IB Questionbank Physics 21

22 (a) The diagram shows how the displacement of the water surface at a particular instant in time varies with distance from the sphere. The period of oscillation of the sphere is s. Use the diagram to calculate, for the wave, (i) the amplitude. (ii) the wavelength. (iii) the frequency. IB Questionbank Physics 22

23 (iv) the speed. (b) The wave moves from region A into a region B of shallower water. The waves move more slowly in region B. The diagram (not to scale) shows some of the wavefronts in region A. (i) With reference to a wave, distinguish between a ray and a wavefront. (2) IB Questionbank Physics 23

24 (ii) The angle between the wavefronts and the interface in region A is 60. The refractive index A n B is 1.4. Determine the angle between the wavefronts and the interface in region B. (2) (iii) On the diagram above, construct three lines to show the position of three wavefronts in region B. (2) (c) Another sphere is dipped into the water. The spheres oscillate in phase. The diagram shows some lines in region A along which the disturbance of the water surface is a minimum. IB Questionbank Physics 24

25 (i) Outline how the regions of minimum disturbance occur on the surface. (3) (ii) The frequency of oscillation of the spheres is increased. State and explain how this will affect the positions of minimum disturbance. (2) (Total 15 marks) 17. This question is about water waves. A small sphere, mounted at the end of a vertical rod, dips below the surface of shallow water in a tray. The sphere is driven vertically up and down by a motor attached to the rod. The oscillations of the sphere produce travelling waves on the surface of the water. IB Questionbank Physics 25

26 (a) State what is meant by a travelling (progressive) wave (b) The diagram shows how the displacement of the water surface at a particular instant in time varies with distance from the sphere. The period of oscillation of the sphere is s. Use the diagram to calculate, for the wave, (i) the amplitude. (ii) the wavelength. IB Questionbank Physics 26

27 (iii) the frequency. (iv) the speed. (c) The wave moves from region A into a region B of shallower water. The waves move more slowly in region B. The diagram (not to scale) shows some of the wavefronts in region A. (i) On the diagram, draw three lines to complete the wavefronts in region B. (2) IB Questionbank Physics 27

28 (ii) Theory suggests that the wave speed c is related to the water depth d by c = gd where g is a constant. The refractive index for waves travelling from region A to region B is 1.4. Determine the following ratio. water depth in A water depth in B (3) (d) Another sphere is dipped into the water. The spheres oscillate in phase. The diagram shows some lines in region A along which the disturbance of the water surface is a minimum. IB Questionbank Physics 28

29 (i) Outline how the regions of minimum disturbance occur on the surface. (3) (ii) The frequency of oscillation of the spheres is increased. State and explain how this will affect the positions of minimum disturbance. (2) (Total 15 marks) 18. The shock absorbers of a car, in good working condition, ensure that the vertical oscillations of the car are A. undamped. B. lightly damped. C. moderately damped. D. critically damped. (Total 1 mark) IB Questionbank Physics 29

30 19. The graphs show how the acceleration a of four different particles varies with their displacement x. Which of the particles is executing simple harmonic motion? (Total 1 mark) IB Questionbank Physics 30

31 20. The diagram below is a snapshot of wave fronts of circular waves emitted by a point source S at the surface of water. The source vibrates at a frequency f = 10.0 Hz. The speed of the wave front is A cm s 1. B. 1.5 cm s 1. C. 15 cm s 1. D. 30 cm s 1. (Total 1 mark) IB Questionbank Physics 31

32 21. This question is about oscillations and waves. (a) A rectangular piece of wood of length l floats in water with its axis vertical as shown in diagram 1. The length of wood below the surface is d. The wood is pushed vertically downwards a distance A such that a length of wood is still above the water surface as shown in diagram 2. The wood is then released and oscillates vertically. At the instant shown in diagram 3, the wood is moving downwards and the length of wood beneath the surface is d + x. (i) On diagram 3, draw an arrow to show the direction of the acceleration of the wood. (ii) The acceleration a of the wood (in m s 2 ) is related to x (in m) by the following equation. a = 14 l Explain why this equation shows that the wood is executing simple harmonic motion. x (2) IB Questionbank Physics 32

33 (iii) The period of oscillation of the wood is 1.4 s. Show that the length l of the wood is 0.70 m. (3) (b) The wood in (a), as shown in diagram 2, is released at time t = 0. On the axes below, sketch a graph to show how the velocity v of the wood varies with time over one period of oscillation. (c) The distance A that the wood is initially pushed down is 0.12 m. (i) Calculate the magnitude of the maximum acceleration of the wood. (2) (ii) On your sketch graph in (b) label with the letter P one point where the magnitude of the acceleration is a maximum. IB Questionbank Physics 33

34 (d) The oscillations of the wood generate waves in the water of wavelength 0.45 m. The graph shows how the displacement D, of the water surface at a particular distance from the wood varies with time t. Using the graph, calculate the (i) speed of the waves. (2) (ii) ratio of the displacement at t = 1.75 s to the displacement at t = 0.35 s. (2) IB Questionbank Physics 34

35 (iii) ratio of the energy of the wave at t = 1.75 s to the energy at t = 0.35 s (Total 15 marks) 22. Two coherent point sources S 1 and S 2 emit spherical waves. Which of the following best describes the intensity of the waves at P and Q? P Q A. maximum minimum B. minimum maximum C. maximum maximum D. minimum minimum (Total 1 mark) IB Questionbank Physics 35

36 23. The shock absorbers of a car, in good working condition, ensure that the vertical oscillations of the car are A. undamped. B. lightly damped. C. moderately damped. D. critically damped. (Total 1 mark) IB Questionbank Physics 36