1. Telecommunication 1.1 – Communication Using Waves

2. Sound and Light Energy Sound and light are important types of energy. We use them to transmit (send) signals from one place to another. This is known as communication. Transmitting (sending) signals over a long distance is known as telecommunication.

3. Activity 1 – Sound and Light Energy For each case, record: 1.the type of energy used 2.a short description of how the energy is used to communicate Example Light – used to communicate with pedestrians when it is safe to cross the road.

4. Sound – used to have a conversation. Sound – used to transmit (send) signals over long distance AB

5. Sound – used to indicate start of a race. Sound – used to attract attention or start/stop sport. CD

6. Sound – used to raise alarm or signal school periods. Sound – used to start races or stir a crowd at sports event. EF

7. Light – used to communicate with other ships Light – use to communicate emergency situation GH

8. Light – used to warn ships of land. Light – used to warn people of an emergency vehicle IJ

9. Light – used to communicate with motorists Light – used to allows motorists to communicate with one another KL

10. Speed of Sound and Light In air, speed of sound is: In air, speed of light is:

11. Use the word bank to complete the passage below. hearlesslight lightningseesound immediatelythunder During a storm, thunder and lightning are produced at exactly the same time. We the before we the because in air the speed of is than the speed of. The travels so fast it reaches us almost. hear see lightning thunder soundlight immediately less

12. Tutorial 1 – Speed of Sound and Light in Air 1.At a fireworks display, a rocket explodes high above your head, producing a loud explosion and a bright flash of light at the same time. (a)What will reach you first – sound of explosion or flash of light? (b)Explain why. 2.On a golf course, you observe a golfer in the distance hitting a golf ball with her club. (a)What will you observe first – the ball moving through the air or the sound of the club hitting the ball? (b)Explain why.

13. 1.At a fireworks display, a rocket explodes high above your head, producing a loud explosion and a bright flash of light at the same time. (a)What will reach you first – sound of explosion or flash of light? (b)Explain why. Answer (a)The flash of light will reach you before the sound of the explosion. (b)The flash of light reaches you before the sound of the explosion because the speed of light in air is much greater than the speed of sound in air.

14. 2.On a golf course, you observe a golfer in the distance hitting a golf ball with her club. (a)What will you observe first – the ball moving through the air or the sound of the club hitting the ball? (b)Explain why. Answer (a)The golf ball moving through the air will be observed first. (b)The golf ball moving through the air is observed first because the speed of light in air is much greater than the speed of sound in air.

15. Distance, Time and Speed x ÷ d v t We can use this relationship (formula) to solve problems about sound travelling through the air (or even other materials). distance unit: m time unit: s speed unit: ms -1

16. Example 1 How long will it take a sound wave to travel a distance 1.5 km? When answering calculation questions, show all working and use the layout shown.

17. Tutorial 2 - Distance, Time and Speed of Sound Calculations 1.Calculate the distance sound will travel through the air in 2 s. 2.How far will the sound of an explosion travel through the air in 5 s? 3.Calculate the time it will take sound to travel 1,020 m through the air. 4.How long will it take the sound of a bell to travel 850 m through the air? 5.Calculate the speed of sound in air if it takes 4 s for the sound to travel 1.36 km. 6.The sound of a car horn is heard 1.19 km away, 3.5 s after it has been sounded. Calculate the speed of the horn sound in air.

18. 7.Susan shouts at a brick wall. After 0.8 s she hears an “echo” – the sound of her shout reflected off the wall. Calculate how far away from the wall Susan is. BE CAREFUL! – It might help if you draw the path taken by the sound on the diagram. Sound has a different speed in different materials. ** Do not need to remember these values **

19. 8.A steel wire is 6.76 km long. Calculate the time it will take sound to travel along the wire. 9.To find the depth of water beneath its hull, a fishing boat sends a pulse of sound through the water from its hull to the sea bed. After 1.2 s, the fishing boat detects the sound pulse reflected from the sea bed. How deep is the sea?

20. 1.Calculate the distance sound will travel through the air in 2 s. 2.How far will the sound of an explosion travel through the air in 5 s?

21. 3.Calculate the time it will take sound to travel 1,020 m through the air. 4.How long will it take the sound of a bell to travel 850 m through the air?

22. 5.Calculate the speed of sound in air if it takes 4 s for the sound to travel 1.36 km. 6.The sound of a car horn is heard 1.19 km away, 3.5 s after it has been sounded. Calculate the speed of the horn sound in air.

23. 7.Susan shouts at a brick wall. After 0.8 s she hears an “echo” – the sound of her shout reflected off the wall. Calculate how far away from the wall Susan is. BE CAREFUL! – It might help if you draw the path taken by the sound on the diagram. transmitted sound reflected sound sound travels to the wall and back distance from the wall is only half of this distance

24. 8.A steel wire is 6.76 km long. Calculate the time it will take sound to travel along the wire.

25. 9.To find the depth of water beneath its hull, a fishing boat sends a pulse of sound through the water from its hull to the sea bed. After 1.2 s, the fishing boat detects the sound pulse reflected from the sea bed. How deep is the sea? sound transmitted sound reflected sound travels to the seabed and back depth of seabed is only half of this distance

26. Measuring Speed of Sound We can perform an experiment to measure the speed of sound in air. microphone B microphone A hammer and metal plate distance (1m) electronic timer

27. The distance between the two microphone is measured using a metre stick. A sharp noise is made near microphone A. The time taken for the sound to travel between A and B is measured using an electronic timer. The speed of sound is calculated using:

28. Results MeasurementTime (micro seconds) 1 2 3 4 5 Average Calculation

29. 1.(a)What value for the speed of sound in air do you obtain? (b)How could you improve the experiment? Answer (a) (b)

30. Scientific Prefixes PrefixSymbolFactor Scientific Notation kilokx 1,000x10 3 megaMx 1,000,000x10 6 gigaGx 1,000,000,000x10 9 millim  1,000x10 -3 microμ  1,000,000x10 -6 nanon  1,000,000,000x10 -9

31. Tutorial 3 – Scientific Notation and Prefixes Yellow Book Basic Mathematics - Page 1 Q1, 3, 4, 5, 6 and 7

32. Answers 1.(a) (b) (c) (d) (e) (f) 3.(a) (b) (c) (d) (e) (f)

33. 4.(a) (b) (c) (d) (e) (f) 5.(a) (b) (c) (d) (e) (f)

34. 6.(a) (b) (c) (d) (e) (f) 7.(a) (b) (c) (d)

35. Light Light is the fastest thing there is - nothing can travel faster than light! Since light travels so fast, we see things happen immediately. This lets us calculate how far away we are from an event taking place. The time between us seeing something happen and hearing it happen is the time it takes for the sound to reach us. Because we know the speed of sound in air, we can apply the formula:

36. Tutorial 4 - Distance, Time and Speed of Light Calculation 1.During a storm, thunder and lightning are produced at exactly the same time. (a)You see a flash of lightning. After 5s, you hear the thunder. How far away from you is the storm? (b)A while later, you see another flash of lightning – but, this time, you hear the thunder after only 1.5 s. How far away from you is the storm now?

37. 2.You see a flare exploding in the distance. After 3.5 s you hear the sound from the explosion. How far away from you was the flare when it exploded? 3.A soldier sees a shell explode. The sound from the explosion reaches him 0.2 s later. How far away from the soldier did the shell explode?

38. 1.During a storm, thunder and lightning are produced at exactly the same time. (a)You see a flash of lightning. After 5s, you hear the thunder. How far away from you is the storm? (b)A while later, you see another flash of lightning – but, this time, you hear the thunder after only 1.5 s. How far away from you is the storm now? (a) (b)

39. 2.You see a flare exploding in the distance. After 3.5 s you hear the sound from the explosion. How far away from you was the flare when it exploded?

40. 3.A soldier sees a shell explode. The sound from the explosion reaches him 0.2 s later. How far away from the soldier did the shell explode?

41. Waves and Energy Water waves on the sea or a pond are easy to see. All waves transfer (carry) g from one place to another. A tsunami sea wave transfers an enormous amount of which can cause extensive damage when the wave reaches land. energy

42. Waves & Signal Transmission Sound and light signals are transmitted (sent) from one place to another by g. also transmit signals for: waves Waves radio television mobile phones satellites

43. Wave Diagrams The diagram below represents a typical wave when viewed from the side. Use the word bank to complete the diagram. amplitude wavelength amplitudecrest wavelengthtrough

44. crest trough wavelength ( λ ) amplitude wavelength ( λ ) amplitude wavelength amplitudecrest wavelengthtrough

45. These diagrams represent waves viewed from above. The lines show the middle of wave crests. No wave troughs are shown. On each diagram show the wavelength. straight waves circular waves λ λ

46. Describing Waves Use the word/symbol bank to complete the table. above distance amplitude secondwavelength below fHzλmmms -1 v

47. QuantitySymbolUnitDescription wave crestpart of wave central line wave troughpart of wave central line ( ) height of wave crest or wave trough measured from the centre line the higher the of a wave, the more energy it carries lambda ( ) distance between two identical neighbouring points on a wave, e.g. distance between two neighbouring crests frequency( ) number of wavelengths (or crests or troughs) per. speed( ) wave travels every second periodTstime taken to produce one wave above below amplitude second distance λ Hz wavelength amplitude ms -1 m m f v

48. The frequency of a wave is: number of whole waves produced in one second This can be represented by the formula: x ÷ N f t number of waves unit: NONE time unit: s frequency unit: Hz

49. The speed of a wave is: distance travelled by a wave in one second This can be represented by the formula: x ÷ d v t distance unit: m time unit: s speed unit: ms -1

50. Tutorial 5 – Water Wave Calculations 1.(a)Which of these waves is carrying the most energy? (b)Explain your answer. 2.The wave shown is travelling to the right. (a)As the wave travels, what happens to its amplitude? (b)What must be happening to the waves energy? AB

51. 3.(a)State the value for this wave’s: (i)amplitude(ii)wavelength 0 0.2 0.4 0.81.21.6 (metres) (b)This wave was produced in 1 second. State the value of its frequency. 4.Determine the frequency of the wave in each case. (a)5 wavelengths are produced every second. (b)10 water waves pass the end of a pier in 2 seconds. (c)12 circular waves spread across a pond in 20 seconds.

52. 5.(a)For this wave, state the value of: (i) the amplitude (ii) the wavelength 0.8 m 0.2 m (b)The wave is produced in 2 seconds. State the value for its frequency. 6.(a)Determine the wavelength of these water waves. (b)These five wave crests were produced in 25 seconds. Determine the frequency of the waves. 20 m

53. 7.(a)What is the wavelength of these circular water waves. (b)The three wave crests were produced in 0.5 seconds. What is the wave frequency? 6 m 8.A tsunami sea wave takes 6 s to travel up a beach with a speed of 15 ms -1. What distance does the wave travel up the beach? 9.When Sajidha threw a stone into a pond, circular waves travelled 7.5 m across the water in 2.5 s. Calculate the speed of these water waves.

54. 10.Sea waves approach a cliff at 4 ms -1. What time will the waves take to travel 20 m? 11.Sid the surfer rides the crest of a sea wave travelling at 6 ms -1 for 8 s. Calculate how far the wave carries Sid in this time. 12.A drop of water from a leaking tap causes waves on the surface of Brenda’s bath water. If these waves travel 0.4 m in 1.6 s, at what speed are they travelling?

55. 13.As the tide goes out, sea waves travel 50m with a speed of 2.5 ms -1. How long do the waves take to travel this distance?

56. The Wave Formula The time taken for one wave to be produced is the period. The frequency and period of a wave are related by: One complete wave (1λ) is produced in a time of one period (T). This wave will travel a distance (d) of one wavelength (1λ) in a time of one period (T).

57. wave will travel one whole wavelength (1λ) in the time it takes to produce one whole wave (the period – T) x ÷ v f λ speed unit: ms -1 wavelength unit: m frequency unit: Hz Equivalence of the 2 Wave Formula

58. Tutorial 6 – Speed, Wavelength and Frequency Calculations 1.Calculate the speed of water waves which have a frequency of 2 Hz and wavelength of 5 m. 2.Calculate the frequency of water waves in a harbour if they travel at 3 ms -1 and have a wavelength of 4 m. 3.Calculate the wavelength of water waves on a pond which travel at 0.75 ms -1 and have a frequency of 1.5 Hz. 4.Every second, two waves are produced on Alan’s bath water by water dripping from a tap. If these waves have a wavelength of 0.05 m, calculate the speed. 5.The wind causes waves to travel across a puddle at 2.4 ms -1. If the waves have a wavelength of 0.6 m, determine their frequency. 6.A wave generator in a swimming pool produces 2.5 waves every second. The waves travel across the pool at 1.2 ms -1. Determine their wavelength. 7.Calculate the speed of sound waves in air which have a frequency of 0.5 kHz and a wavelength of 0.34 m.

59. 8.Calculate the frequency of sound waves in air which have a wavelength of 1.7 m. 9.Calculate the wavelength of sound waves in air which have a frequency of 0.8 kHz. 10.A submarine sends a pulse of sound through the sea. Determine the speed of the sound pulse if it has a frequency of 7.5 kHz and a wavelength of 0.2 m. 11.Sound travels through steel at 5,200 ms -1. In the steel, sound waves have a wavelength of 2m. Calculate the frequency. 12.Ultrasound (frequency of 21 kHz) travels through human muscle at 1,600 ms -1. Calculate the wavelength of the ultrasound in the muscle.

60. 1.Calculate the speed of water waves which have a frequency of 2 Hz and wavelength of 5 m. 2.Calculate the frequency of water waves in a harbour if they travel at 3 ms -1 and have a wavelength of 4 m.

61. 3.Calculate the wavelength of water waves on a pond which travel at 0.75 ms -1 and have a frequency of 1.5 Hz. 4.Every second, two waves are produced on Alan’s bath water by water dripping from a tap. If these waves have a wavelength of 0.05 m, calculate the speed.

62. 5.The wind causes waves to travel across a puddle at 2.4 ms -1. If the waves have a wavelength of 0.6 m, determine their frequency. 6.A wave generator in a swimming pool produces 2.5 waves every second. The waves travel across the pool at 1.2 ms -1. Determine their wavelength.

63. 7.Calculate the speed of sound waves in air which have a frequency of 0.5 kHz and a wavelength of 0.34 m. 8.Calculate the frequency of sound waves in air which have a wavelength of 1.7 m.

64. 9.Calculate the wavelength of sound waves in air which have a frequency of 0.8 kHz. 10.A submarine sends a pulse of sound through the sea. Determine the speed of the sound pulse if it has a frequency of 7.5 kHz and a wavelength of 0.2 m.

65. 11.Sound travels through steel at 5,200 ms -1. In the steel, sound waves have a wavelength of 2m. Calculate the frequency. 12.Ultrasound (frequency of 21 kHz) travels through human muscle at 1,600 ms -1. Calculate the wavelength of the ultrasound in the muscle.