Chapter 1 Waves Exercise

Revision March 2013 Physics Form 5

1. Figure shows a simple pendulum which consists of a bob of mass 40.0 g at the end of a light inelastic string of length 20.0 cm. The pendulum makes 20 complete oscillations in 5.0 s.

(a) By using the letters A,B and C in the figure above state the meaning of

(i) equilibrium position

...............................................................................................................................................................................................................(1m)(ii) period

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(b) What is the frequency of the oscillations of the pendulum ?

(2m)

(c) What is the frequency of the oscillations of the pendulum when a bob of mass 50.0 g is used?

(2m)(d) What happens to the frequency of the oscillations of the pendulum when the length of the pendulum is 80.0 cm ?

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(e) After a while the pendulum stops to oscillate , explain why?

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(f) Plot a graph displacement – time to show why the pendulum stops to oscillate.

(g) State the form of energy when the pendulum(i) at B

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(ii) between B and C

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TUTORIAL 1(a)

CHAPTER 1: WAVES 1.1 understanding waves

Revision March 2013 Physics Form 52. A trolley rests on a horizontal frictionless surface and is connected to two walls by two steel springs. The trolley vibrates with its natural frequency when it is pulled aside and released.

(a) What is meant by the natural frequency ?

...............................................................................................................................................................................................................(1m)

(b) What will happen to the nature frequency of the both springs when(i) the steel springs are replaced by the cooper springs.

...............................................................................................................................................................................................................(1m)(ii) the number of trolley is increased.

...............................................................................................................................................................................................................(1m) (iii) the experiment is conducted at the surface of the Moon.

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(c) When the amplitude of the vibrations remain constant, draw, using the same axes shown below, two displacement- time graphs to compare the vibrations of the springs with one trolley and then with two trolleys are used.

(2m)

3 A student carries out an experiment to find out the relationship between mass, m and the oscillation period, T of a piece of jigsaw blade. The jigsaw blade is clamped at one end and a plasticine ball with mass, m is fixed at the other end as shown in figure below.

The jigsaw blade is displaced horizontally to one side and then released so that it oscillates. The time for 20 oscillations ,t is taken by a stop watch. The experiment is repeated by using plasticine balls with different masses.The results of the experiment are shown in the table below.

Mass,m /k g

Time for 20oscillations, t / s

Period, T / s T2 / s2

0.1 28.00.2 40.00.3 50.00.4 56.00.5 64.00.6 70.0

(3m) (a) Complete the table above.

(b) Based on the graph paper above plot a graph T2 against

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(5m)(c) Based on your graph state the relationship between T and m.

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(d) Determine the value of (i) m when T = 2.2 s

(2m) (ii) T when m = 0.72 kg.

(2m)(e) State one precaution that should be taken during this experiment.

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Figure 1Figure 2

Figure 1 shows a spring of load before and after the load is displaced and released to vibrate on the surface of water.Figure 2 shows a candle flame is placed in front of a loudspeaker before and after the audio-frequency generator is switched on to prodeuce a sound.Observe Figure 1 and Figure 2.

(a) (i) Compare the condition of the water surface and candle flame when the load vibrate and the audio-frequency generator is switched on.

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(ii) Relate the observations in (a)(i) and the transfer of enegy to deduce a concept in physics with regard to the wave motion

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...............................................................................................................................................................................................................(2m) (b) (i) Compare the direction of vibration of the

particles and the direction of wave propagation.

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T UTORIAL 1(b)

Revision March 2013 Physics Form 5 (ii) Based on your answer in b(i) name the type of wave in

Figure 1 ..............................................................................................................................................................................(1m)

Figure 2 ..............................................................................................................................................................................(1m)

2 The figure shows a graph displacement-distance for a transverse wave.

(a) Mark on the graph (i) the direction of vibration of the particles and the direction of wave propagation . (1m)(ii) two points vibrate in phase. (1m)

(b) Give one example of the transverse wave .

...............................................................................................................................................................................................................(1m) (c) Determine

(i) the amplitude

(1m) (ii) the wavelength

(1m)

(d) What is the speed of the wave when the frequency is 25 Hz.

(2m)

(f) Give one example of the natural phenomenon to show that a wave transfer energy.

...............................................................................................................................................................................................................(1m)

3 The figure shows a student setting up waves on a long lastic cord . The studen’s hand makes 5 complete up-and -down movement in 2. 5 s, and in each up-and-down movement the hand moves through a height of 0.4 m.P , Q, R, S and T are the points marked on the cord.

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(a) What type of wave is produced by the cord?

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(b) State two points that out of phase.

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(c) Determine (i) the amplitude

(1m)(ii) the frequency

(2m)(iii) the speed of the wave

(2m)(d) What happens to distance of PR when frequency of the waves increase?

...............................................................................................................................................................................................................(1m)

(2m)

1 The figure shows plane water waves is produced by a vibrating wooden bar vibrates at a rate 15 waves per second.

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CHAPTER 1: WAVES 1.2 reflection of waves

T UTORIAL 1(c)


(a) From the figure above(i) Mark the direction of the propagation of the water waves. (1m)(ii) Determine the wavelength of the waves.

…………………………………………(1m)(iii) Calculate the speed of the water waves.

(2m)(b) A plane reflector is placed at different inclined angle in front of the water waves as shown in the following figure. Draw the

pattern of the reflected wave in the figure.(2m)

(i)(ii)

2 Determine by way of ray diagrams, the cars that can be seen by the driver through reflection of rays by the rear view mirror.

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(2m)

1 The figure shows successive wavefronts of waves travelling on the surface of water a ripple tank.A perspex plat is placed on the bottom of a ripple tank .

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CHAPTER 1: WAVES 1.3 refraction of waves

T UTORIAL 1(d)


(a) By drawing a straight line on the figure above mark the boundary of the perspex plat.

(1m)(b) (i) Determine the wavelength of the waves before travels over the perspex plat.

(1m)

(ii) Calculate the frequency of the waves before travels over the perspex plat when the velocity is 40 cms-1.

(2m)(iii) Determine the velocity of the waves travels over the perspex plat.

(2m)

(c) Explain why the water waves propagated from the sea to the beach , the water waves follow the shape of the beach.

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2 Figure 1 shows a water waves in a ripple tank travels over a perspex plat.Figure 2 shows a water waves propagated from the sea to the beach.

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Figure 1 Figure 2(a) Based on Figure 1 and Figure 2(i) state the change in wavelength of the water waves from A to B.

...............................................................................................................................................................................................................(1m)

(ii) compare the depth of water between A and B.

...............................................................................................................................................................................................................(1m)(iii) name a physical quantity is unchanged .

...............................................................................................................................................................................................................(1m) (b) Relate your answer in (a)(i) and (a)(ii) to deduce a wave phenomenon.

...............................................................................................................................................................................................................(1m)(c) Name the phenomenon in (b)

...............................................................................................................................................................................................................(1m)(d) (e) The water waves with a wavelength of 1.5 m travels with velocity 2.0 ms-1 from the sea to the beach. The velocity

of the waves when reach near the beach is 1.2 ms-1 .Calculate ,(i) the frequency of the waves

(2m)](ii) the wavelength of the waves near the beach

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CHAPTER 1: WAVES 1.4 diffraction of wavesT UTORIAL 1(e)

Revision March 2013 Physics Form 51 Figure 1 shows a plane water waves of passing through a small slit.

Figure 2 shows a plane water waves passing through a small obstacle.

Figure 1 Figure 2

(a) Observe Figure 1 and Figure 2 and state two similarities of the wave patterns.

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...............................................................................................................................................................................................................(2m) (b) Relate your answers in (a) to deduce a relevant physics concept and name the concept.

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2 The figure shows the bright and dark bands of the wave patterns formed on the screen when plane waves pass through narrow and wide slits.

Observe the figure. Compare the wave patterns and the wavelengths of the waves before and after they pass through the slits.Relate the size of slits, the wave patterns and the wavelengths to deduce a relevant physics concept.Name the wave phenomenon shown in the figure.

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1 The figure shows a plane water waves approaches two small slits .

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CHAPTER 1: WAVES 1.5 interference of wavesT UTORIAL 1(f)


(a) Mark a point where constructive interference occurs and a point where destructive interference occurs,(b) What is another phenomenon involved?

...............................................................................................................................................................................................................(1m)(a) When the frequency of the vibrator MN is 12 Hz, what is the speed of the water waves

2 The figure shows the arrangement of apparatus to investigate the phenomena of light waves. The sodium-vapour lamp is adjusted until the position of the lamp is at the focus point of the lense.

(a) Why is The sodium-vapour lamp is adjusted until the position of the lamp is at the focus point of the lense?

...............................................................................................................................................................................................................(1m)

(b) (i) In the box below ,draw and label the pattern of image is formed on the screen.

(ii) Name the light phenomenon involved.

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Revision March 2013 Physics Form 5...............................................................................................................................................................................................................(1m)

(c) The single slit is replaced by a double slit of slit separation is 5 x 10-4 m.(i) In the box below ,draw and label the pattern of image is formed on the screen.

(ii) Name the light phenomenon involved.

...............................................................................................................................................................................................................(1m) (iii) The light emits from the sodium-vapour lamp with a wavelength of 6.0 x 10-7m.Calculate the distance two consecutive

bright fringes.

(d) When the experiment is carried out in the water, what happen to

(i) the wavelength of the light waves?

...............................................................................................................................................................................................................(1m) (ii) the distance two consecutive bright fringes.

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3 The figure shows the arrangement of apparatus in Young’s double slit experiment and the pattern of the fringes formed o the screen.

(a) What happen to the wave of lights when passed through the slits.

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(b) Explain briefly how the fringes are formed?

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...................................................................................................................(2m)

(c) The monochoromatic light is used is blue light. What happen to the distance two consecutive bright fringes when

(i) the distance between the screen and the double slit is increased.

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(ii) the slit separation is decreased

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(iii) the blue light is replaced by a red light

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(d) If D = 3.0 m , a= 5.2 x 10 –3 m , determine the wavelength of the wave of the lights.

4. The figure shows the pattern of the fringe formed on the screen from Young’s double slit experiment.The experiment used and a red filter and then is repeated by using a blue filter to produce a monochromatic light.

(a) What s meant by a monochromatic light?

...............................................................................................................................................................................................................(1m) (b) Using the pattern of the fringes in the figure above , state two observations about the distances between consecutive

fringes for the red light and the blue light................................................................................................................................................................................................................(1m)

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(c) Compare the wavelengths of red light to blue light.

...............................................................................................................................................................................................................(1m) (d) Relate the wavelengths of red light to blue light with the distances between consecutive fringes in(b).

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...............................................................................................................................................................................................................(1m) (e) Name the wave phenomenon which forms the pattern of the fringes in the figure above.

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5 The figure shows the arrangement of apparatus in the interference wave of sounds experiment. Two similar loudspeakers are placed 2.0 m apart. A source of sound is switched on to produce a sound of frequency 2.4 kHzA girl walks slowly along OP parallel to the two loudspeakers at a distance 5.0 m in front of the loudspeakers. She hears loud sound at point A ,C and E and alternately weak sound at point B,C and D.

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(a) Name the source of the sound waves is used.

...............................................................................................................................................................................................................(1m) (b) Two loudspeakers is used to produce a coherent wave. What is meant by a coherent wave?

...............................................................................................................................................................................................................(1m)

(c) Name the wave phenomenon involved.

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(d) What happen to the sound wave at point

(i) A,C and E

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(ii) B,D and F

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(e) When the speed of sound waves is 360 ms-1, determine(i) the wavelength of the sound waves.

(ii) the distance AF

1 A boy stands at point P between two high walls P and Q. The distance between P and T is 100 m and the distance

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CHAPTER 1: WAVES 1.6 SOUND WAVEST UTORIAL 1(g)

Revision March 2013 Physics Form 5From T and Q is 500 m. He shouts in front of the high walls. He hears the echo of his voice from the high wall P and 2.5 seconds later he hears the echo of his voice from the high wall Q.

(a) What is meant by echo?

......................................................................................................... (1m) (b) Determine the speed of the sound waves.

(c) When the distance between two high walls are increased what happen to (i) the speed of the sound waves.

...............................................................................................................................................................................................................(1m)(ii) the time taken to hear the echo

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2 The figure shows ultrasound being used to study an unborn baby.(a) What is meant by ultrasound?

......................................................................................................(1m)

(b) Explain how the waves is used to scan the baby?

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(c) Why using this method to scan an unborn baby is safer than using X-rays?

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(d) Ultrasound used in medicine has a frequency which is about 100 times higher than the maximum frequency that can be heard by humans. If the speed of ultrasound in the human body is 1 500 ms-1, determine (i) the frequency that might be used for ultrasound in medicine.

(ii) the wavelength of the ultrasound in the human body.

1 The figure shows the electromagnetic spectrum.

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CHAPTER 1: WAVES 1.7 ELECTROMAGNETIC WAVE

T UTORIAL 1(h)


(a) Name the waves mark by

(i) P ………………………………………(ii) Q ………………………………………(iii) R ……………………………………..

(b) What is the speed of the electromagnetic waves in vacuum?

...............................................................................................................................................................................................................(1m) (c) Name an apparatus to detect gamma rays.

...............................................................................................................................................................................................................(1m) (d) Name a source to produce Q.

...............................................................................................................................................................................................................(1m)(e) Name a wave can cause skin burns

...............................................................................................................................................................................................................(1m)(f) Complete the following table.

Uses Electromagnetic wavesatellite transmissionsto identify counterfeit notes

3 The diagram represents the electromagnetic spectrum.

(a) Name the type of electromagnetic radiation that is used(i) to sterelise surgical instruments.: …………………………………………..(ii) to send a signal to a TV from a remote control.: …………………………………………..

(b) Valuable item can be security marked using special ink . The ink can only be seen in ultraviolet radiation

Explain what happen to make this ink visible?

...............................................................................................................................................................................................................(1m)(c) Explain why skin cells need to be protected from ultraviolet radiation?

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Chapter 1 Waves Exercise

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