Sound — Paper 3 · IGCSE Physics 0625

7 Fig. 7.1 shows how the air pressure at one instant varies with distance along the path of a For continuous sound wave. Examiner’s Use air pressure normal P X Y air pressure distance in direction of travel of the wave Fig. 7.1 (a) What type of waves are sound waves? … [1] (b) On Fig. 7.1, mark on the axis PY (i) one point C where there is a compression in the wave, [1] (ii) one point R where there is a rarefaction in the wave. [1] (c) Describe the motion of a group of air particles situated on the path of the wave shown in Fig. 7.1. … … … [2] (d) The sound wave shown has speed of 340 m / s and a frequency of 200 Hz. Calculate the distance represented by PX on Fig. 7.1. distance = … [2]

7 marks

Mark scheme: 7 (a) Longitudinal or pressure waves B1 1 (b) a correct C marked B1 a correct R marked B1 2 (c) oscillation/vibration/backwards and forwards M1 along PY (consider pressure waves as alternative) A1 2 (d) wavelength = 340/200 C1 PX(= λ /2) = 0.85 m A1 2 [7]

This question in 0625/31 May/June 2006

7 Two students are asked to determine the speed of sound in air on the school playing fields. (a) List the apparatus they need. … … … [1] (b) List the readings that the students need to take. … … … [1] (c) State how the speed of sound is calculated from the readings. … [1] (d) State one precaution that could be taken to improve the accuracy of the value obtained. … … [1] (e) The table gives some speeds. speed/ speed of sound speed of sound m/s in air in water 10 100 1000 10 000 Place a tick in the table to show the speed which is closest to (i) the speed of sound in air, (ii) the speed of sound in water. [2] [Total: 6]

6 marks

Mark scheme: 7 (a) source of sound (e.g. gun/hooter), tape (100 m), stopwatch B1 [1] NOT clock, metre rule (unless lab method) (b) distance and time between “flash and bang” (must be clear) B1 [1] (c) distance/time OR d/t OR 2d/t B1 [1] (d) further apart/more accurate timer/repeat/any other B1 [1] (e) speed of sound in air, tick 100 B1 speed of sound in water, tick 1000 B1 [2] [Total: 6]

This question in 0625/31 May/June 2007

7 A disused railway line has a length of 300 m. A man puts his ear against one end of the rail For and another man hits the other end with a metal hammer, as shown in Fig. 7.1. Examiner’s Use hammer railway man with ear hits rail line against rail 300 m Fig. 7.1 (a) (i) State an approximate value for the speed of sound in air. … [1] (ii) Sound travels at 5000 m / s in steel. Calculate the time it takes for the sound to travel along the rail. time taken = … [2] (b) The man with his ear to the railway line actually hears two sounds from the hammer, separated by a short interval. Explain why he hears two sounds. … … … … [2] [Total: 5]

5 marks

Mark scheme: 7 (a) (i) approximately 330 m/s (correct order of magnitude) B1 (ii) 300 / 5000 OR t = d/v NOT t = 2d/v C1 0.06 s A1 (b) sound through air and sound through steel NOT echo B1 speeds in air and steel are different NOT if faster in air accept sound in steel/rail heard first B1 [5]

This question in 0625/32 May/June 2010

7 A disused railway line has a length of 300 m. A man puts his ear against one end of the rail For and another man hits the other end with a metal hammer, as shown in Fig. 7.1. Examiner’s Use hammer railway man with ear hits rail line against rail 300 m Fig. 7.1 (a) (i) State an approximate value for the speed of sound in air. … [1] (ii) Sound travels at 5000 m / s in steel. Calculate the time it takes for the sound to travel along the rail. time taken = … [2] (b) The man with his ear to the railway line actually hears two sounds from the hammer, separated by a short interval. Explain why he hears two sounds. … … … … [2] [Total: 5]

5 marks

Mark scheme: 7 (a) (i) approximately 330 m/s (correct order of magnitude) B1 (ii) 300 / 5000 OR t = d/v NOT t = 2d/v C1 0.06 s A1 (b) sound through air and sound through steel NOT echo B1 speeds in air and steel are different NOT if faster in air accept sound in steel/rail heard first B1 [5]

This question in 0625/33 May/June 2010

7 (a) State an approximate value for (i) the speed of sound in air, … (ii) the speed of light in air. … [2] (b) Use your value from (a)(i) to calculate the frequency of a sound wave that has a wavelength of 1.2 m. frequency = … [2] (c) A meteorologist observes an approaching thunderstorm and records a time difference of 4.8 s between seeing a lightning flash and hearing the thunder that follows. (i) Calculate the distance of the thunderstorm from the meteorologist. distance = … (ii) State an assumption you made when calculating this distance. … … … [2] [Total: 6]

6 marks

Mark scheme: 7 (a) (i) 320-350 m/s condone 100 – 999 m/s B1 (ii) 3 × 108 m/s condone 2 – 4 × 108 m/s B1 [2] (b) use of v = fλ C1 correct evaluation of candidate’s (a)(i)/1.2 (330 m/s gives 275 Hz) A1 [2] (c) (i) correct evaluation of candidate’s (a)(i) × 4.8 (330 m/s gives 1584m) B1 IGCSE – October/November 2011 0625 32 (ii) clear statement that light travels instantaneously o.w.t.t.e. OR distance of thunderstorm same as distance travelled by sound OR thunder and lightning caused by same event OR negligible wind B1 [2]

This question in 0625/32 Oct/Nov 2011

8 Fig. 8.1 shows a loudspeaker cone oscillating to produce sound waves. cone oscillates to produce sound waves loudspeaker cone Fig. 8.1 (a) As the sound wave passes a point, it produces regions of higher and lower pressure. State the names of these regions. higher pressure … lower pressure … [2] (b) Describe how the movement of the loudspeaker cone produces these regions of different pressure. higher pressure … … lower pressure … … [2] (c) State the effect on the loudness and pitch of the sound from the loudspeaker when (i) the amplitude increases but the frequency of the sound stays the same, loudness … pitch … (ii) the amplitude stays the same but the frequency increases. loudness … pitch … [2] [Total: 6]

6 marks

Mark scheme: 8 (a) compression B1 rarefaction B1 [2] (b) cone moves forward / in direction of travel of wave OR cone pushes air particles closer o.w.t.t.e. B1 cone moves backwards / away from direction of travel of wave OR cone causes empty spaces o.w.t.t.e. B1 [2] (c) (i) loudness increases AND pitch same B1 (ii) loudness same AND pitch increases B1 [2]

This question in 0625/32 Oct/Nov 2011

8 (a) State the range of frequencies of sound which can be heard by a healthy human ear. For Examiner’s … [1] Use (b) Compressions and rarefactions occur along the path of sound waves. State, in terms of the behaviour of molecules, what is meant by (i) a compression, … … (ii) a rarefaction. … … [2] (c) State the effect on what is heard by a listener when there is (i) an increase in the amplitude of a sound, … [1] (ii) a decrease in the wavelength of a sound. … [1] (d) A student carries out an experiment to find the speed of sound in air. He stands facing a high cliff and shouts. He hears the echo 1.9 s later. He then walks 250 m further away from the cliff and shouts again, hearing the echo 3.5 s later. Calculate the speed of sound given by this experiment. speed = … [3] [Total: 8]

8 marks

Mark scheme: 8 (a) 15–25 Hz to 15 000–25 000 Hz / 15–25 kHz B1 (b) (i) (region) where air layers/molecules/particles are pushed together/moved together/ closer (than normal) OR (region) where (air) pressure raised/air (more) compressed/more dense B1 (ii) (region) where air layers/molecules are pushed apart/far(ther) apart (than normal) OR (region) where (air) pressure reduced/air expanded B1 (c) (i) (sound is) loud(er) OR volume (of sound is) increased B1 (ii) sound has a higher frequency/pitch OR higher note (heard) B1 (d) 3.5 – 1.9 OR 1.6 (s) seen OR v = 2d /1.9 C1 250 × 2 OR 500 (m) seen OR v = (2d + 500)/3.5 C1 (speed = 500 / 1.6 =) 312.5 m / s at least 2 sig. figs A1 [Total 8]

This question in 0625/31 May/June 2013

6 (a) Draw a straight line from each wave to the most appropriate speed on the right. For Examiner’s Use wave speed 15 m / s (1.5 × 10 m / s) 300 m / s (3 × 102 m / s) light in air 1500 m / s (1.5 × 103 m / s) sound in air 1 500 000 m / s (1.5 × 106 m / s) sound in water 300 000 000 m / s (3 × 108 m / s) 1 500 000 000 m / s (1.5 × 109 m / s) [3] (b) Fig. 6.1 shows a railway-line testing-team checking a continuous rail of length 120 m. The diagram is not to scale. earphone steel rail hammer sensor Fig. 6.1 (not to scale) One tester strikes one end of the rail with a hammer. The other tester hears the sound For transmitted through the air and transmitted through the rail. He hears the two sounds at Examiner’s different times. Use The speed of sound in steel is 5000 m / s. Calculate the time difference, using your value from (a) for the speed of sound in air. time difference = … [4] [Total: 7]

7 marks

Mark scheme: 6 (a) light in air BOX 5 3 × 108 m / s B1 sound in air BOX 2 300 m / s B1 sound in water BOX 3 1500 m / s B1 [3] (b) distance = speed × time in any form NOT speed = 2d/t C1 tair = 120 ÷ value for speed of sound in air C1 trail (= 120 / 5000) = 0.024 s C1 (time difference =) candidate’s tair – candidate’s trail correctly evaluated (expect 0.400 – 0.024 = 0.376 s) A1 [4] [Total: 7]

This question in 0625/32 Oct/Nov 2013

8 (a) Draw a straight line from each quantity on the left-hand side to a speed on the right-hand side which is typical for that quantity. 30 m / s 300 m / s speed of sound in gas 3000 m / s speed of sound in solid 30 000 m / s 300 000 m / s [2] (b) Explain why sound waves are described as longitudinal. … … [2] (c) Fig. 8.1 shows how the displacement of air molecules, at an instant of time, varies with distance along the path of a sound wave. displacement 0 0 distance along path of sound wave Fig. 8.1 (i) On Fig. 8.1, sketch two cycles of a sound wave that has a shorter wavelength and a greater amplitude. [2] (ii) State two changes in the sound heard from this wave compared with the original wave. 1. … 2. … [2] [Total: 8]

8 marks

Mark scheme: 8 (a) speed of sound in gas: 300 m / s B1 speed of sound in solid: 3000 m / s B1 (b) particles / molecules / atoms oscillate / vibrate OR pressure variation / compressions / rarefactions / displacements move B1 in the direction of travel (of the wave / sound) B1 (c) (i) two complete wavelengths / cycles with shorter wavelength B1 wave drawn has greater amplitude B1 (ii) higher frequency / pitch B1 louder / higher volume B1 [Total: 8]

This question in 0625/31 May/June 2014

7 (a) State how a longitudinal wave differs from a transverse wave. … … … [2] (b) A sound wave of frequency 7.5 kHz travels through a steel beam at a speed of 6100 m / s. (i) Calculate the wavelength of this sound wave in the steel beam. wavelength = … [2] (ii) The sound wave passes from the end of the beam into air. State 1. the effect on the speed of the sound, … [1] 2. the effect on the wavelength of the sound. … [1] [Total: 6]

6 marks

Mark scheme: 7 (a) vibrations OR compressions AND rarefactions M1 vibrations parallel to direction of travel (of wave energy) OR compressions move in direction of travel (of wave energy) A1 (b) (i) (ä=)v / f OR 6100 / 7500 OR 6100 / 7.5 C1 0.81(33333) m OR 813(33333) mm A1 (ii) 1. decreases B1 2. same answer as 1. B1 [Total: 6]

This question in 0625/33 May/June 2014

7 (a) A police car siren emits sound waves that vary in pitch. Tick two boxes that apply to the sound waves emitted by the siren. electromagnetic longitudinal transverse visible frequency 0.1–10 Hz frequency 100–10 000 Hz frequency 100 000–1 000 000 Hz [2] (b) Fig. 7.1 is a top view of one wavefront of a water wave before it strikes a hard boundary. boundary direction of travel wavefront of wavefront Fig. 7.1 (i) Name the process that occurs as the wavefront strikes the boundary. … [1] (ii) Explain, in terms of wave theory, what occurs as the wavefront strikes the boundary. … … … … … [2] (iii) State whether there is an increase, a decrease or no change in the wavelength of the wave after it strikes the boundary. … [1] (iv) The speed of the wave is 3.0 m / s and its wavelength 7.0 cm. Calculate the frequency of the wave. frequency = … [2] [Total: 8]

8 marks

Mark scheme: 7 (a) longitudinal (2nd box) B1 frequency 100 – 10 000 Hz (6th box) B1 (note: –1 for e.e.o.o) (b) (i) reflection B1 (ii) any two from: • new wave(fronts/lets) generated • same speed OR frequency • angle of incidence = angle of reflection OR wavefronts make same angle (with boundary) B2 (iii) no change B1 (iv) v/λ OR v = fλ in any form C1 (f = 3.0/0.07 =) 43 Hz A1 [Total: 8]

This question in 0625/32 Oct/Nov 2014

7 (a) Underline the most appropriate value below for the speed of sound in water. [1] 1.5 m / s 15 m / s 150 m / s 1 500 m / s 15 000 m / s (b) Sound travels in water as a series of compressions and rarefactions. Describe what is meant by a compression and by a rarefaction. compression … … rarefaction … … [2] (c) An echo-sounder sends out a pulse of sound to determine the depth of the sea bed. It measures the time between sending out the pulse and receiving its echo. Fig. 7.1 shows a boat using an echo-sounder. echo-sounder 12 m echo pulse of sound sea bed Fig. 7.1 The sea bed is 12 m below the echo-sounder. (i) Use your value for the speed of sound in water from (a) to calculate the time between the sending out of the pulse and receiving its echo. time = … [3] (ii) The boat passes over a region of the sea bed of the same depth, where the reflection of sound waves is weaker. State whether there is an increase, a decrease or no change in the amplitude and pitch of the reflected wave. amplitude … pitch … [2] [Total: 8]

8 marks

Mark scheme: 7 (a) 1500 m / s underlined / indicated B1 (b) compression: closer together AND rarefaction: further apart B1 compression: particles / molecules / wavefronts closer together / low pressure AND rarefaction: particles / molecules / wavefronts further apart / high pressure B1 (c) (i) (t =) d / v used OR t = 2d / v OR 12 / 1500 OR 0.008 (s) C1 (t =) 2d / v used OR 24 / 1500 C1 0.016 s A1 (ii) amplitude: decrease B1 pitch: no change B1 [Total: 8]

This question in 0625/33 Oct/Nov 2014

5 (a) Fig. 5.1 shows a metal strip, held in a clamp. metal strip X Y Z clamp Fig. 5.1 The end of the strip is pulled down and released, so that the strip vibrates. X and Z are the extreme positions of the end of the strip during this vibration. Y is the mid-position. Explain what is meant by (i) the frequency of vibration of the strip, … … (ii) the amplitude of vibration of the end of the strip. … … [2] (b) Fig. 5.2 shows two tall buildings, A and B, that are 99 m apart. 99 m A B P 33 m Fig. 5.2 (not to scale) A student stands at P so that his distance from building A is 33 m. After clapping his hands once, he hears several echoes. The speed of sound in air is 330 m / s. Calculate the time interval between clapping his hands and hearing (i) the first echo, time = … [2] (ii) the third echo. time = … [1] (c) Write down an approximate value for the speed of sound (i) in water, speed = … (ii) in steel. speed = … [2] (d) Fig. 5.3 shows a dolphin in water emitting a sound wave of frequency 95 kHz. Fig. 5.3 (not to scale) Using your value from (c)(i), calculate the wavelength of this sound wave. wavelength = … [2] [Total: 9]

9 marks

Mark scheme: 5 (a) (i) (number of complete) vibrations (of the strip) per second/unit time B1 (ii) maximum displacement of end of strip from mid-position OR XY OR ZY OR XZ ÷ 2 B1 (b) (i) (t =) d ÷ v OR 2d ÷ v C1 0.20 s OR 0.2 s A1 (ii) 0.60 s OR 0.6 s c.a.o. B1 (c) (i) accept any value between 1.0 and 9.9 × 103 m / s B1 (ii) accept any value between 1.0 and 9.9 × 103 m / s B1 (d) v = fλ in any form OR v ÷ f C1 correct evaluation from candidate’s (c)(i) with unit, expect 0.016 m B1

This question in 0625/32 May/June 2015

7 (a) A sound wave in air consists of alternate compressions and rarefactions along its path. (i) Explain how a compression differs from a rarefaction. … … [1] (ii) Explain, in terms of compressions, what is meant by 1. the wavelength of the sound, … … [1] 2. the frequency of the sound. … … [1] (b) At night, bats emit pulses of sound to detect obstacles and prey. The speed of sound in air is 340 m / s. (i) A bat emits a pulse of sound of wavelength 0.0085 m. Calculate the frequency of the sound. frequency = … [2] (ii) State why this sound cannot be heard by human beings. … … [1] (iii) The pulse of sound hits a stationary object and is reflected back to the bat. The pulse is received by the bat 0.12 s after it was emitted. Calculate the distance travelled by the pulse of sound during this time. distance = … [2] [Total: 8]

8 marks

Mark scheme: 7 (a) (i) (compression is a) region of higher pressure OR region where air layers/particles/molecules are closer B1 (ii) 1. distance between (two successive / adjacent) compressions B1 2. number of compressions (passing a point) per second / unit time OR number of compressions emitted per second/unit time B1 (b) (i) (f = ) v /λ OR 340 / 0.0085 C1 40 000 Hz OR 40 kHz A1 (ii) frequency/pitch is above the upper threshold for human hearing / 20 kHz OR it is ultrasound B1 (iii) (d =) vt in any form: words, symbols, numbers C1 41 m or 40.8 m A1 [Total: 8]

This question in 0625/33 May/June 2015

6 A sound wave, travelling in air, approaches a solid barrier with a gap in the middle. Fig. 6.1 represents the compressions and rarefactions of the sound wave. The compressions are labelled A, B and C. barrier A B C compression rarefaction Fig. 6.1 (a) State how a compression differs from a rarefaction. … … [1] (b) The speed of sound in air is 340 m / s. The frequency of the sound is 850 Hz. For this wave, determine (i) the wavelength, wavelength = … [2] (ii) the time that elapses before compression A reaches the barrier. time = … [2] (c) On Fig. 6.1, draw the shape and positions of compressions B and C as compression A reaches the barrier. [2] (d) Sound waves can also travel in water. State how the speed of sound in water compares with the speed of sound in air. … [1] [Total: 8]

8 marks

Mark scheme: 6 (a) (in compressions) pressure higher OR molecules / atoms / particles close(r) together / (more) tightly packed B1 (b) (i) v = fλ in any form OR (λ =) v / f OR 340 / 850 C1 = 0.40 m A1 (ii) distance (of compression A from barrier) = 2.5 × 0.40 OR 1.0 m C1 time (to reach barrier) = 1 / 340 = 2.9 × 10–3 s OR 2.9 ms A1 OR T (= 1 / f) = 1 / 850 OR 0.4 / 340 OR 1.2 × 10–3 (C1) (moves 2.5 wavelengths:) time = 2.5 / 850 = 2.9 × 10–3 s OR 2.9 ms (A1) (c) two circular arcs centred on mid-point of gap in barrier by eye B1 along centre line, arcs separated by the same distance as adjacent compressions approaching barrier B1 (d) (speed in water) greater OR numerical value greater than 340 m / s B1 [Total: 8]

This question in 0625/31 Oct/Nov 2015

8 (a) Some students want to determine the speed of sound in air. Describe a method they could use. Include the measurements they must make. … … … … … … … … … … … … [4] (b) The graph in Fig. 8.1 represents a sound wave. displacement B A C D F 0 E distance Fig. 8.1 (i) Which distance represents the amplitude of the wave? Circle your answer. [1] AC AF BE DE CF (ii) Which distance represents the wavelength of the wave? Circle your answer. [1] AC AF BE DE CF (iii) Another sound wave, of the same wavelength, is louder. On Fig. 8.1, draw this wave. [2] [Total: 8]

8 marks

Mark scheme: 8 (a) for full marks the method described must work any four from: B4 • means of producing sharp sound • use of suitable reflecting surface • measure total distance travelled by sound • measurement of time for sound to travel measured distance. • use of speed = distance / time (b) (i) circle around DE B1 (ii) circle around CF B1 (iii) higher amplitude drawn B1 same wavelength drawn (by eye) B1 [Total: 8]

This question in 0625/32 Feb/March 2016

8 A cruise ship has a firework display near a cliff as shown in Fig. 8.1. cliff exploding firework 1.0 km 1.0 km cruise ship container ship Fig. 8.1 (not to scale) A firework is sent into the air from the cruise ship. The firework explodes with a bright flash of light and a loud bang. (a) People on a container ship see the flash before they hear the bang. Explain why. … … [2] (b) The people on the container ship hear two bangs. They hear the second bang shortly after the first bang. (i) Explain why they hear two bangs. … … [2] (ii) The speed of sound in air is 330 m / s. The firework explodes at a distance of 1.0 km from the container ship. 1. Calculate the time for the first bang to reach the people on the container ship. time = … s [3] 2. Estimate the time delay between hearing the first bang and second bang. time = … s [1] [Total: 8]

8 marks

Mark scheme: 8(a) indication of speeds / velocity B1 light quickest B1 8(b)(i) echo / reflection (of sound) B1 from cliff B1 8(b)(ii) speed = distance ÷ time in any recognised form C1 1000 ÷ 330 C1 3.03 (s) A1 5–7 seconds B1 Total: 8

This question in 0625/32 Feb/March 2017

9 Fig. 9.1 shows the position of a man working in a rock quarry. A single explosion is used to break part of one rock face. explosion front back rock rock face face man 170 m 430 m Fig. 9.1 (a) Explain why the man sees the flash of the explosion before he hears the bang. … … [1] (b) The man hears a second bang shortly after the first bang. (i) State the name given to this second bang. … [1] (ii) State how the second bang compares with the first bang in terms of its amplitude and speed. amplitude … speed … [2] (c) The man stands 170 m from the back rock face. The time between hearing the first bang and hearing the second bang is 1.0 s. Use the information in Fig. 9.1 to determine the speed of sound in the quarry. speed of sound = … m / s [3] [Total: 7]

7 marks

Mark scheme: 9(a) light travels faster than sound or converse argument B1 9(b)(i) echo B1 9(b)(ii) amplitude – smaller B1 speed – the same B1 9(c) speed = distance ÷ time C1 170 + 170 OR 340 ÷ 1 C1 340 (m / s) A1 Total: 7

This question in 0625/31 May/June 2017

7 Fig. 7.1 shows the regions of the electromagnetic spectrum. radio infra-red ultraviolet microwaves 1 X-rays 2 waves waves waves Fig. 7.1 (a) (i) Give the names of the two regions that are labelled 1 and 2. 1. … 2. … [2] (ii) Use words from the box to complete the sentence. acceleration amplitude frequency speed wavelength Compared with other regions in the electromagnetic spectrum, radio waves have the largest … and the smallest … . [2] (b) Sound is not an electromagnetic wave. Give one other way in which sound waves are different from radio waves. … [1] (c) Two students, X and Y, carry out an experiment to determine the speed of sound in air. X has two blocks of wood that make a loud, sharp sound when banged together. Y has a tape measure and a stopwatch. Describe how X and Y can use the equipment to measure the speed of sound in air. … … … … … … [4] [Total: 9]

9 marks

Mark scheme: 7(a)(i) visible light B1 gamma rays B1 7(a)(ii) wavelength B1 frequency B1 7(b) (sound) is a longitudinal wave (radio waves are transverse) (sound) needs a medium to be transmitted (but radio waves do not) B1 7(c) any four from: only award 4 marks if valid procedure (use tape measure) to measure distance of at least 100 m blocks banged together stopwatch started when blocks are SEEN to hit stopwatch stopped when sound heard time taken recorded/calculated speed = distance ÷ time B4 Total: 9

This question in 0625/32 May/June 2017

7 A sound wave is a longitudinal wave. Fig. 7.1 shows a spring being used to demonstrate a longitudinal wave. direction of spring wave travel coils Fig. 7.1 (a) The coils of the spring vibrate. Draw two arrows on Fig. 7.1 to show the directions of the vibrations. [2] (b) Through which of these is sound not able to travel? Tick one box. air steel vacuum water [1] (c) (i) Very old people cannot hear the highest frequencies of sound that can be heard by young people. Suggest the highest frequency that very old people can hear. … [2] (ii) State the meaning of the term ultrasound. … [1] [Total: 6]

6 marks

Mark scheme: 7(a) horizontal arrows by eye B1 arrows pointing in opposite directions B1 7(b) 3rd box ticked vacuum B1 7(c)(i) value less than 20 000 B1 Hz B1 7(c)(ii) sound with frequency above upper (frequency) limit of human hearing B1 Total: 6

This question in 0625/33 May/June 2017

7 (a) Fig. 7.1 shows a man listening to a radio. X centre of loudspeaker Fig. 7.1 (i) Sound from the radio makes an air particle at X vibrate. On Fig. 7.1 draw two arrows on point X to show the directions of vibration of the air particle. [2] (ii) Which of these terms correctly describes the sound wave? Tick one box. transverse longitudinal electromagnetic [1] (iii) Suggest a value for the frequency of the sound that the man can hear. State the unit. frequency = … [2] (iv) Explain why the man cannot hear ultrasound. … … [1] (b) Fig. 7.2 shows a distance-time graph for ultrasound travelling in sea-water. 1000 distance / m 800 600 400 200 0 0 0.20 0.40 0.60 0.80 time / s Fig. 7.2 (i) Use the graph to calculate the speed of ultrasound in sea-water. speed = … m / s [2] (ii) A scientist measures the depth of the sea by using ultrasound. She sends a pulse of ultrasound from the ship to the seabed. It reflects from the seabed as shown in Fig. 7.3. reflection pulse of ultrasound Fig. 7.3 The time taken between sending a pulse and receiving the echo is 0.60 s. Use the graph to determine the depth of the sea. depth = … m [2]

10 marks

Mark scheme: 7(a)(i) arrows horizontal / on line from radio to man B1 arrows in opposite direction B1 7(a)(ii) middle box ticked longitudinal B1 7(a)(iii) number in range 20–20 000 B1 hertz B1 7(a)(iv) (frequency of ultrasound) is above human (hearing) range B1 7(b)(i) speed = dist ÷ time or any two corresponding values of distance ÷ time e.g. 600 ÷ 0.4 C1 1500 (m / s) A1 7(b)(ii) 900 (m) read from graph C1 depth = 450 (m) A1

This question in 0625/31 Oct/Nov 2017

12 Fig. 12.1 shows some equipment used in a demonstration. wires from battery rubber bung electric bell glass jar hammer gong to vacuum pump Fig. 12.1 The glass jar is connected to a vacuum pump. The electric bell is switched on. The observers see and hear the bell working. (a) (i) The vacuum pump removes air from the glass jar. State what the observers see and what they hear after the air is removed. observers see … … observers hear … … [2] (ii) State what the demonstration in (a)(i) shows about the transmission of sound waves. … … … [2] (iii) When the bell is working, the hammer strikes the gong. Describe how the gong produces the sound. … … [1] (b) Indicate the lowest and highest frequencies that can be heard by the human ear. Tick one box from each column. lowest frequency highest frequency 2 Hz 20 kHz 20 Hz 200 kHz 200 Hz 2 MHz 2 kHz 20 MHz [2] [Total: 7]

7 marks

Mark scheme: 12(a)(i) electric bell working owtte B1 no sound from bell / bell is quieter B1 12(a)(ii) any two from: sound will travel through air / glass sound will not cross a vacuum sound needs a medium to travel through B2 12(a)(iii) vibrations B1 12(b) 20 Hz from first column B1 20 kHz from second column B1

This question in 0625/32 Oct/Nov 2017

9 A machine pushes a metal post into the ground using a hammer, as shown in Fig. 9.1. The hammer makes a loud noise when it hits the post. hammer machine post Fig. 9.1 A man stands 160 m from the hammer. (a) A man sees the hammer hit the post and a short time later hears the sound of the post being hit. Explain the delay in hearing the sound. … … [1] (b) (i) The hammer is 320 m from a large building as shown in Fig. 9.2. large building 320 m 160 m machine man post Fig. 9.2 The man hears the hammer hit the post and then hears an echo. Explain why he hears the echo. … … [1] (ii) The speed of sound in air is 320 m / s. Calculate the time difference between the man hearing the first sound and the time at which he hears the echo. time difference = … [3] (c) Suggest how the sound of the echo is different from the first sound. … [1] [Total: 6]

6 marks

Mark scheme: 9(a) light travels faster than sound OR reverse argument B1 9(b) reflection (from building) / bouncing back (from building) B1 9(c) time taken for first sound = 0.5 s C1 Time taken for echo = 2.5 s OR time for sound to travel from hammer and return = 2.0 s C1 2.0 s A1 9(d) quieter / less amplitude / less energy B1

This question in 0625/33 Oct/Nov 2017

8 This question is about measuring the speed of sound in air. A student stands in front of a large wall. She hits a drum and hears an echo. Fig. 8.1 shows the position of the student and the wall. wall student Fig. 8.1 (a) (i) State the name of a piece of equipment for measuring the distance from the student to the wall. … [1] (ii) Explain how sound forms an echo. … … [1] (b) The student hits her drum repeatedly once per second. She walks away from the wall and listens for the echo. When the student is 170 m from the wall she hears the echo from one beat of the drum at the same time as the next beat of the drum. Use this information to determine the speed of sound. State the unit. speed = … [4] [Total: 6]

6 marks

Mark scheme: 8(a)(i) tape measure 1 8(a)(ii) reflection (of sound) 1 8(b) time for sound to travel to wall and back = 1.0 s 1 340 m in 1.0 s 1 (speed =) 340 1 m / s 1

This question in 0625/31 May/June 2018

8 (a) Complete the sentences about sound. Use words from the box above each sentence. (i) glows reflects refracts vibrates Sound is produced when a source … . [1] (ii) electromagnetic longitudinal transverse Sound waves are … waves. [1] (iii) metal vacuum liquid Sound waves cannot travel through a … . [1] (b) Humans, elephants, mice and dolphins have different hearing ranges. Fig. 8.1 shows the hearing range for each type of animal. 1000 000 100 000 frequency / Hz 10 000 1000 100 10 0 humans elephants mice dolphins Fig. 8.1 (i) State the lowest frequency of sound that can be heard by mice. … Hz [1] (ii) State the highest frequency of sound that can be heard by elephants. … Hz [1] (iii) Explain how the chart shows that elephants can hear some sounds that humans cannot hear. … … … [2] (iv) State the term given to the high frequencies that dolphins can hear but humans cannot hear. … [1] [Total: 8]

8 marks

Mark scheme: 8(a)(i) vibrates 1 8(a)(ii) longitudinal 1 8(a)(iii) vacuum 1 8(b)(i) 1000 (Hz) 1 8(b)(ii) frequency in range 10 001 to 30 000 (Hz) 1 8(b)(iii) lowest frequency heard by humans is 20 Hz 1 (but) elephants can hear frequencies below 20 Hz 1 8(b)(iv) ultrasound 1

This question in 0625/32 May/June 2018

8 (a) The boxes contain words about waves. Complete each sentence. Choose a term from each box. (i) an electromagnetic a longitudinal a transverse Sound travels as … wave. [1] (ii) amplitude pitch speed wavelength A loud sound has a large … . [1] (iii) amplitude pitch speed wavelength A student listens to two sounds. The sound with the higher frequency has a higher … . [1] (b) Explain what is meant by the term ultrasound. … … [2] [Total: 5]

5 marks

Mark scheme: 8(a)(i) Longitudinal 1 8(a)(ii) Amplitude 1 8(a)(iii) pitch 1 8(b) frequencies (of sound) 1 above 20 000 Hz 1

This question in 0625/33 May/June 2018

8 (a) Fig. 8.1 shows a tuning fork and a wooden block. tuning fork wooden block Fig. 8.1 (i) The tuning fork is hit against the wooden block and then makes a sound. Describe how the tuning fork produces the sound. … … [1] (ii) The tuning fork produces a sound with a frequency of 659 Hz. State whether a healthy human ear can hear this frequency of sound. Explain your answer. … … [2] (b) Fig. 8.2 represents the sound wave produced by a tuning fork. time Fig. 8.2 A second tuning fork produces a different sound. Compared with the sound represented in Fig. 8.2, this sound is quieter and has half the frequency. On Fig. 8.2, draw the wave to show the sound produced by the second tuning fork. [2] [Total: 5]

5 marks

Mark scheme: 8(a)(i) vibrates B1 8(a)(ii) Yes B1 (as within audible range of) 20 Hz to 20 000 Hz B1 8(b) line drawn with smaller amplitude B1 lower frequency i.e. fewer waves on screen B1

This question in 0625/31 Oct/Nov 2018

8 (a) A healthy human ear can hear a range of frequencies. Three frequency ranges are shown. Draw a ring around the range for a healthy human ear. 0 Hz – 20 Hz 10 Hz – 10 000 Hz 20 Hz – 20 000 Hz [1] (b) Explain the meaning of the term ultrasound. … … [2] (c) A student listens to two different sounds, P and Q. The two different sounds are represented on a computer screen on the same scale. Fig. 8.1 shows the screens. sound P sound Q Fig. 8.1 State and explain how sound P is different from sound Q. … … … … [3] [Total: 6]

6 marks

Mark scheme: 8(a) circle around 20 Hz–20 000 Hz B1 8(b) frequencies (of sound) B1 above 20 000 Hz B1 8(c) Quieter sound AND has lower pitch B1 (as) smaller amplitude B1 (as) frequency is lower B1

This question in 0625/32 Oct/Nov 2018

7 Some students make statements about sound. In each part of the question, only one statement is correct. Place a tick in the box next to each correct statement. (a) Sound travels at the same speed as light. Sound travels faster than the speed of light. Sound travels slower than the speed of light. [1] (b) Healthy human ears can hear sounds in the range 2.0 Hz to 2000 Hz. Healthy human ears can hear sounds in the range 20 Hz to 20 000 Hz. Healthy human ears can hear sounds in the range 200 Hz to 200 000 Hz. [1] (c) Increasing the amplitude of a sound wave increases its speed. Increasing the amplitude of a sound wave increases its frequency. Increasing the amplitude of a sound wave increases its loudness. [1] (d) An echo is produced when sound is diffracted. An echo is produced when sound is refracted. An echo is produced when sound is reflected. [1] [Total: 4]

4 marks

Mark scheme: 7(a) 3rd box – sound travels slower than the speed of light B1 7(b) 2nd box – 20 to 20000 Hz B1 7(c) 3rd box – Increasing the amplitude of a sound wave increases its loudness B1 7(d) 3rd box – an echo is produced when sound is reflected B1

This question in 0625/33 Oct/Nov 2018

8 (a) Fig. 8.1 shows a student listening to the sound produced by a tuning fork. tuning fork Fig. 8.1 (i) State how the tuning fork produces the sound. … [1] (ii) Complete the following sentence. Choose a word from the box. electromagnetic longitudinal transverse A sound wave is … [1] (iii) A loudspeaker produces a sound with a frequency of 25 kHz. A student with healthy ears cannot hear this sound. Explain why. … … [2] (b) Fig. 8.2 represents a sound wave travelling in air. Fig. 8.2 (drawn full size) (i) The air particles are moving. On Fig. 8.2, draw two arrows in opposite directions to show the movement of the air particles. [1] (ii) Use Fig. 8.2 to determine the wavelength of the sound wave. wavelength = … cm [1] (c) Describe a method of using water waves to demonstrate refraction. … … … … … … [4] [Total: 10]

10 marks

Mark scheme: 8(a)(i) (it is) vibrating B1 8(a)(ii) longitudinal B1 8(a)(iii) frequency (of sound) OR 25 kHz B1 is above (upper limit of) human hearing range OR is an ultrasound B1 8(b)(i) horizontal line with arrows at either end B1 8(b)(ii) (14.4 ÷ 4 =) 3.6 (cm) B1 8(c) Any four from: use of shallow water use of flat lamina or shape below surface / different depths (of water) used waves hit {shallower water / shape} at an angle (other than 90°) waves change direction (due to) change in speed B4

This question in 0625/31 Oct/Nov 2019

9 A boat race starts on the sea, but close to land. Fig. 9.1 shows the boats at the start of the race. Fig. 9.1 On the land, a cannon produces a loud bang to start the race. There is a flash of light at the same time as the bang. (a) (i) At the start of the race, the sailors watch for the flash of light from the cannon. Suggest why the sailors watch for the flash of light rather than listen for the bang. … … [1] (ii) One of the sailors is 500 m from the cannon. She measures a time difference of 1.6 seconds between seeing the flash of light and hearing the bang. Calculate the speed of sound. speed of sound = … m / s [3] (iii) The value of the speed of sound obtained in (a)(ii) is lower than expected. Suggest a reason for this difference. … … [1] (b) The race is held close to a part of the coast with high cliffs. A sailor hears a second bang shortly after the first bang. State the term for the second bang and explain how it is produced. term … explanation … [2] [Total: 7]

7 marks

Mark scheme: 9(a)(i) light travels faster than sound OR flash / light seen before bang heard B1 9(a)(ii) speed = distance ÷ time in any form C1 500 ÷ 1.6 C1 312.5 (m / s) A1 9(a)(iii) it is windy owtte OR reaction times to start / stop watch B1 9(b) echo B1 (sound) reflected from cliffs B1

This question in 0625/32 Oct/Nov 2019

8 Fig. 8.1 represents the pressure at one instant along part of a sound wave. direction of wave travel above normal air pressure normal air pressure 20 40 60 80 100 120 distance / cm below normal air pressure Fig. 8.1 (a) (i) Determine the wavelength of the sound wave. wavelength of the sound wave = … cm [1] (ii) On Fig. 8.1, draw a wave representing a louder sound of the same wavelength. [1] (b) State the range of audible frequencies for a healthy human ear. Include the unit. … [2] [Total: 4]

4 marks

Mark scheme: 8(a)(i) (wavelength =) 40 (cm) B1 8(a)(ii) wave drawn with greater amplitude B1 8(b) 20 to 20 000 B1 Hz or hertz B1

This question in 0625/31 May/June 2020

8 Sound travels as a wave. (a) Complete each sentence. Sound is produced when an object … . An echo is produced when sound is … from a hard surface. Compared with a quiet sound, a loud sound always has a greater … . Compared with a high pitched sound, a low pitched sound always has a smaller … . Waves transfer energy without transferring … . [5] (b) State the meaning of the term ultrasound. … [1] [Total: 6]

6 marks

Mark scheme: 8(a) vibrates B1 reflected B1 amplitude B1 frequency B1 matter B1 8(b) vibrations with higher frequency than sound B1

This question in 0625/32 May/June 2020

8 Fig. 8.1 shows a mobile (cell) phone. Fig. 8.1 (a) (i) State the type of electromagnetic wave used for the mobile phone signal. … [1] (ii) The screen of the mobile phone emits visible light. State one type of electromagnetic wave with a shorter wavelength than visible light. … [1] (b) The mobile phone produces sound waves. (i) State the range of audible frequencies for a healthy human ear. Include the unit. … [2] (ii) The ring tone of the mobile phone consists of two musical notes, note A and note B. Note A is louder and is higher in pitch than note B. Fig. 8.2 shows note A displayed on an oscilloscope screen. Fig. 8.2 Note B is displayed on the same oscilloscope screen as note A. Describe the differences between the wave for note B and the wave for note A. You may draw on Fig. 8.2 to show the differences. … … [2] [Total: 6]

6 marks

Mark scheme: 8(a)(i) microwave B1 8(a)(ii) ultraviolet / UV OR X-ray OR γ- / gamma (rays) B1 8(b)(i) 20 to 20 000 B1 Hz or hertz B1 8(b)(ii) (note B has) smaller amplitude OR note A has larger amplitude B1 (note B has) lower frequency OR longer wavelength OR note A has higher frequency OR shorter wavelength B1

This question in 0625/31 Oct/Nov 2020

8 (a) A loudspeaker is producing a sound. Choose words from the box to complete the sentences about sound. amplitude frequency speed wavelength (i) To increase the loudness of the sound, increase the … of the sound wave. [1] (ii) To increase the pitch of the sound, increase the … of the sound wave. [1] (b) Two students determine the speed of sound in air. The students stand together, 80 m from a large brick wall as shown in Fig. 8.1. brick wall 80 m Fig. 8.1 (not to scale) One student shouts and as he shouts the other student starts a stop-watch. She stops the stop-watch when she hears the echo of the shout. The reading on the stop-watch is 0.56 s. (i) State the total distance the sound travels during the 0.56 s. distance = … m [1] (ii) Calculate the speed of sound in air using the measurements given in part (b). speed of sound = … m / s [3] (iii) The students’ value for the speed of sound is not accurate. Suggest two ways of improving the students’ experiment. 1. … 2. … [2] [Total: 8]

8 marks

Mark scheme: 8(a)(i) amplitude B1 8(a)(ii) frequency B1 8(b)(i) 160 (m) B1 8(b)(ii) (s = ) d ÷ t (speed of sound =) distance ÷ time C1 160 ÷ 0.56 C1 290 (m / s) A1 8(b)(iii) any two from: use something to give sharper sound stand further away from wall no other walls nearby both students stand at 80 (m)/same distance (from wall) repeat (the measurement/experiment) AND average (results) B2

This question in 0625/31 May/June 2021

6 (a) Fig. 6.1 shows part of a water wave. R height P Q 0 S distance T Fig. 6.1 (i) State the letter P, Q, R, S or T on Fig. 6.1 that represents the wavelength of the water wave. … [1] (ii) State the letter P, Q, R, S or T on Fig. 6.1 that represents the amplitude of the water wave. … [1] (iii) State what is meant by the term frequency of a wave. … … [1] (b) Two students, A and B, use echoes to measure the speed of sound. Student A has two blocks of wood that make a loud sound when banged together. Student B has a stop‑watch. They stand 120 m from a school wall as shown in Fig. 6.2. stop-watch school wall blocks of wood B A 120 m Fig. 6.2 (not to scale) Describe how the students use the arrangement in Fig. 6.2 to determine the speed of sound in air. … … … … … … … [4] [Total: 7]

7 marks

Mark scheme: 6(a)(i) R B1 6(a)(ii) P B1 6(a)(iii) idea of: number of (complete) waves {sent out or produced or passing a point} {in one second or unit time} B1 6(b) any four from: (student A) bangs two blocks of wood together (student B) starts stopwatch when (sees) blocks or wood collide (student B) stops stopwatch when she hears echo repeat (experiment) AND calculate average (time) uses 240 m as distance travelled by sound owtte use s= d ÷ t B4

This question in 0625/31 Oct/Nov 2021

7 Two students, A and B, determine the speed of sound. They are standing side by side at a distance of 520 m from a wall, as shown in Fig. 7.1. 520 m wall B A Fig. 7.1 Student A makes a loud sound by banging two blocks of wood together once. A short time later, both students hear the sound reflected from the wall. (a) (i) State the term for the reflected sound. … [1] (ii) Table 7.1 lists properties of a sound wave. Compare the properties of the original sound and the reflected sound. For each property, place a tick (✓) in one column. The first property is done for you. Table 7.1 property same different speed ✓ wavelength loudness frequency amplitude longitudinal [3] (b) Student B measures the time between the original sound and the reflected sound. (i) Suggest a suitable device for measuring the time interval between hearing the original sound and hearing the reflected sound. … [1] (ii) The time interval between hearing the original sound and hearing the reflected sound is 3.1 s. Use information shown in Fig. 7.1 to calculate the speed of sound. speed of sound = … m / s [3] [Total: 8]

8 marks

Mark scheme: 7(a)(i) echo B1 7(a)(ii) B3 property same different speed ✓ wavelength ✓ loudness ✓ frequency ✓ amplitude ✓ longitudinal ✓ 7(b)(i) stopwatch B1 7(b)(ii) 340 (m / s) A3 (2  520) ÷ 3.1 OR 1040 ÷ 3.1 (C2) (distance =) 2  520 OR 1040 OR (speed =) distance ÷ time in any form (C1)

This question in 0625/33 Oct/Nov 2022

5 An observer stands at P and looks into a rock quarry. A small explosion takes place at X in the quarry. Fig. 5.1 shows the situation. Z P solid rock Y DANGER – X small BLASTING explosion rock quarry Fig. 5.1 (not to scale) (a) The observer first hears the sound from the explosion 1.8 s after the explosion occurs. The speed of the sound is 340 m / s. (i) Calculate the distance XP from the explosion at X to the observer at P. distance XP = … m [3] (ii) The observer then hears a quieter sound from the explosion. Suggest how the quieter sound waves reach the observer. … … [2] (b) Before the explosion, a warning siren produces a sound. The wavelength of the sound is 0.28 m. The speed of the sound is 340 m / s. Calculate the frequency of the sound. frequency = … Hz [3] [Total: 8]

8 marks

Mark scheme: 5(a)(i) 610 (m) A3 340 = distance ÷ 1.8 OR (distance =) 340  1.8 (C2) speed = distance ÷ time in any form (C1) 5(a)(ii) an echo OR sound (waves) reflecting B1 from rocks OR YZ OR Z OR bottom of quarry B1 5(b) 1200 (Hz) A3 340 = f  0.28 OR (f =) 340 ÷ 0.28 (C2) v = f  in any form OR (f =) v ÷  (C1)

This question in 0625/32 May/June 2023

7 A student can hear trains passing her house. (a) Describe the motion that a sound wave gives to air particles. … [1] (b) When the student is at her house, she can hear and see the trains, as shown in Fig. 7.1. house train d whistle river Fig. 7.1 (not to scale) When a train whistle blows, steam comes out of the whistle. The student measures the time interval between seeing the steam coming out of the whistle and hearing the whistle. (i) Suggest a suitable device for measuring this time interval. … [1] (ii) The time interval is 1.6 s between the steam coming out of the whistle and the student hearing the whistle. The speed of sound in air is 340 m / s. Calculate the distance d from the whistle to the student. distance d = … m [3] (c) State the range of audible frequencies for a healthy human ear. Include the unit. … [2] [Total: 7]

7 marks

Mark scheme: 7(a) oscillating / vibrating/backwards and forwards B1 7(b)(i) stopwatch / (stop)clock B1 7(b)(ii) 540 (m) A3 340  1.6 (C1) (distance =) speed  time (C1) 7(c) 20 – 20 000 B1 Hz / hertz B1

This question in 0625/32 Oct/Nov 2023

6 Fig. 6.1 shows some students near some rocky cliffs looking at a boat at sea. The students watch a firework display on the boat. One of the fireworks bursts and makes a loud sound. a firework bursting in air rocky cliffs students boat beach Fig. 6.1 (not to scale) (a) The students hear a loud sound from the firework and then they hear a quieter, similar sound. State what causes the second quieter, similar sound. … [1] (b) The time from when the students see the firework burst to when they hear the first, loud sound is 1.3 s. Calculate the distance from the firework to the students. Use the speed of sound in air = 340 m / s. distance to firework = … m [3] [Total: 4]

4 marks

Mark scheme: 6(a) (sound is) reflected (from cliff ) OR echo (from cliff) B1 6(b) (d =) 440 (m) A3 (d =) 340  1.3 (C2) (d =) s  t OR s = d  t (C1)

This question in 0625/31 Oct/Nov 2024

8 A student strikes a tuning fork on a wooden block. The tuning fork is held close to the students’ ear as shown in Fig. 8.1. Fig. 8.1 (a) Describe how the tuning fork produces sound. … [1] (b) State the normal frequency range of sounds that humans can hear. Give the unit. from … to … [2] (c) Two students determine a value for the speed of sound in air. Fig. 8.2 illustrates the method they use. metal plates clash together stopwatch metal plates 60 m Fig. 8.2 (Not to scale) The girl starts the stopwatch when she sees the metal plates clash together. She stops the stopwatch when she hears the sound of the clashing metal plates. The students use the time on the stopwatch to calculate the speed of sound. The value for the speed of sound obtained by the students is different from the true value for the speed of sound in air. Explain why the students’ value is different. … … … [1] [Total: 4]

4 marks

Mark scheme: 8(b) 20 to 20 000 B1 hertz OR Hz B1 8(c) reaction time B1 OR distance / time interval is too small

This question in 0625/32 Feb/March 2025

4 A group of students are studying a topic called ‘Light and Sound’. (a) Fig. 4.1 shows a demonstration using a noisy toy. air outlet noisy toy transparent box sound proof block Fig. 4.1 The teacher puts the noisy toy into a sealed, transparent case that contains air. The teacher removes the air from inside the case. The sound of the noisy toy becomes quieter until the students cannot hear it. The students can see the toy moving, but cannot hear it, because light and sound have different properties. State three differences between the properties of light and the properties of sound. 1 … 2 … 3 … [3] (b) The students go to a large park to determine the speed of sound. Describe an experiment for determining the speed of sound. You may draw a diagram as part of your answer. … … … … … … … … [4] (c) The students find that the speed of sound is 340 m / s. They strike a tuning fork of frequency 260 Hz. Calculate the wavelength of the sound that the tuning fork produces. wavelength = … m [3] [Total: 10]

10 marks

Mark scheme: 4(a) any three from: B3 • light travels through a vacuum or • sound does not travel through a vacuum / needs a medium owtte • light is transverse (wave – sound isn’t) • sound is longitudinal (wave – light isn’t) • light is electromagnetic / e.m. (wave – sound isn’t) • light travels at different speed than sound (in air) 4(b) two students / groups at least 100 m apart B1 any three from: B3 • distance measured by tape (measure) / trundle wheel • means of making loud sound (that is visible) e.g. wooden blocks • distant student / group start measuring time when sound is made e.g. when blocks colliding seen • distant student / group stop time measurement when sound is heard • (time measured by) stopwatch / stop-clock / timer • repeat (experiment) AND calculate average (time) • use speed = distance ÷ time in any form alternative MS for echo method: B1 two students / group at least 50 m from wall / solid structure any three from: B3 • distance measured by tape (measure) / trundle wheel • means of making loud sound e.g. shouting • another student / group start(s) measuring time when loud noise made • another student / group stop measuring when echo / number of echoes is / are heard • (time measured by) stopwatch / stop-clock / timer • repeat (experiment) AND calculate average (time) or perform sound-echo-sound-echo (n) ⩾ 9 times AND ÷ n • use speed = 2  distance ÷ time 4(c) 1.3 (m) A3 340 ÷ 260 C2 (wavelength =) speed ÷ frequency C1

This question in 0625/32 Oct/Nov 2025