Markscheme: Physics GCSE Waves Questions and homework General Properties of waves. 1. The diagram shows a water wave drawn to scale.

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1 Markscheme: Physics GCSE Waves Questions and homework 2017 General Properties of waves 1. The diagram shows a water wave drawn to scale. (a) What is the wavelength of this water wave?...4cm... cm (1) (b) What is the amplitude?...3 cm... cm (1) (c) Twelve waves pass an observer in four seconds. What is the frequency of the waves? Show clearly how you work out your answer and give the unit....12/ Frequency =...3Hz...(3)[5] 2. The diagram shows some waves travelling along a rope. λ A (a) Carefully show on the diagram (i) the wavelength of one of the waves label this λ (1) (ii) the amplitude of one of the waves label this A (1) (b) The waves shown on the diagram were produced in two seconds. (i) How many complete waves are shown? (ii) What is the frequency of the waves? Hz...(2) (c) The wavelength of a similar wave is 0. I m. Its frequency is 2 Hz. Calculate the speed of the wave. Show clearly how you work out your answer and give the unit....v= fλ = 2 x Speed of wave...0.2m/s...(2) [6]

2 3. (a) Water waves can be made by vibrating a wooden bar up and down in a tray of water. The bar moves up and down at a frequency of 5 hertz. (i) How many complete waves are shown? (ii) Calculate, in centimetres (cm), the wavelength of the water waves. Show clearly how you work out your answer....48/6... Wavelength = cm (2) (ii) Calculate the speed, in c/s, of the water waves. Write down the equation you use and then show clearly how you work out your answer.... λ = 8cm = 0.08m.....v= fλ =5x 0.08 = 0.4 m/s Wave speed = m/s(3) (b) The graph shows how the speed of deep ocean waves depends on the wavelength of the waves. What can you conclude from the graph? The longer the wavelength the greater the speed Speed increases at a decreasing rate...(2) Use the graph to predict a speed for waves with a wavelength of 140 m. Show clearly how you have used the graph to work out your answer. Speed of waves = m/s (2)[8] 4. (a) The diagram shows a longitudinal wave being produced in a stretched spring. (i)use words from the diagram to complete the following sentence. Put one word in each space. A longitudinal wave is one in which the...oscillation causing the wave is parallel to the..direction. of energy transfer. (2)

3 (ii) Which one of the following types of wave is longitudinal? Draw a ring around your answer. light sound radio (1) (b) The diagram shows water waves made by a wave machine in a swimming pool. Every second two waves go past a person standing in the swimming pool. (i) What is the frequency of the water waves?...2 Hz...(1) (ii)the waves have a wavelength of 0.8 metres..calculate the speed of the water waves. Write down the equation you use, and then show clearly how you work out your answer.... v= fλ =2 x Wave speed = 1.6 unit m/s (3) The electromagnetic spectrum 1. (a) gamma rays above x-rays for 1 mark (b) upper radio wave boundary correct (10-1 m) (± 1mm) for 1 mark (c) visible radiation/light within the middle third of a wavelength band in the correct wavelength range ( m) each for 1 mark (d) ultraviolet between *visible radiation and X-rays for 1 mark (e) microwaves above *radio waves and below *infra red for 1 mark (*not necessarily immediately) (f) between 10 8 Hz Hz and nearer to 10 8 Hz than to 10 7 Hz gains 1 mark [7] 2. TYPE OF RADIATION Radio waves Ultra violet Visible light X rays WAVELENGTH (m) 1500 m m m m (b) Hz for 4 marks else for 3 marks

4 else /0.03 for 2 marks else v = frequency wavelength or = 0.03f for 1 mark any answer with unit Hz scores 1, 2 or 3 4[8] 3. (a) Microwaves are one type of electromagnetic wave. (i) Name two higher frequency electromagnetic waves used for communication...light and infra red... (1) (ii) What do all types of electromagnetic wave transfer from one place to another?...energy... (1) (b) The picture shows a tennis coach using a speed gun to measure how fast the player serves the ball. (i) The microwaves transmitted by the speed gun have a frequency of Hz and travel through the air at m/s. Calculate the wavelength of the microwaves emitted from the speed gun. Show clearly how you work out your answer....λ=v.= f Wavelength = m(2) (ii) Some of the microwaves transmitted by the speed gun are absorbed by the ball. What effect will the absorbed microwaves have on the ball?...heat it up... (1) (c) Calculate the wavelength, in metres, of a radio wave which is broadcast at a frequency of 909 khz. Show clearly how you work out your answer khz = Hz... λ=v.= f Wavelength = metres(2) (d) What happens when a metal aerial absorbs radio waves? Electrons in the aerial oscillate Producing an a.c. signal (at the same frequency as the radio wave) (2) (e) Stars emit all types of electromagnetic waves. Telescopes that monitor X rays are mounted on satellites in space. Why would an X ray telescope based on Earth not be able to detect X rays emitted from distant stars? The atmosphere absorbs ( or does not transmit) x rays (1)[10] 4. (a) (i) or correct equivalent 2 allow 1 mark for correct transformation and substitution (of 75) answer gains 1 mark only

5 (b) (i) any mention of alpha, beta, gamma waves scores 0 marks emit / uses / transmit / receive microwaves 1 accept radiation for microwaves throughout ignore radio waves some microwave / energy absorbed by / enters the body 1 ecf for their given electromagnetic wave do not accept goes through the body raises temperature of (body) cells / tissue / water 1 accept reference to water molecules vibrating faster accept it could cause mutation / harm / kill cells do not accept answers in terms of ionization ignore references to cancer (ii) any two from: research (may be) biased or may have been misled in the past accept not independent or may be lying some research suggests a link long term effect not proven / studied accept not studied for long enough residents may not have seen the research 2[7] 5.(a) (i) frequency 1 Wavelength 1 (ii) to (b) correct substitution of / 1500 gains 1 mark Hz 1 (c) (i) (skin) burns 1 (ii) skin cancer / blindness 1 (d) (i) any one from: (detecting) bone fractures (detecting) dental problems treating cancer 1 (ii) any one from: affect photographic film absorbed by bone transmitted by soft tissue kill (cancer) cells answer must link to answer given in (d)(i) 1 (iii) 9 / 36 = / 2 = / 16 = 0.25

6 accept: 36 / 9 = 4 2 / 0.5 = 4 16 / 4 = 4 2 conclusion based on calculation two calculations correct with a valid conclusion scores 2 marks one correct calculation of k scores 1 mark 1[13] 6. (a) (i) to check rise in temperature (of other thermometers) was due to the (different wavelengths of) light accept as a control / comparison to measure room temperature is insufficient 1 (ii) any two from three: different colours produce different heating effects / (rises in) temperatures red light produces the greatest heating effect / (rise in) temperature or violet produces the least heating effect / (rise in) temperature all colours produce a greater heating effect than outside the spectrum an answer the longer the wavelength the greater the (rise in) temperature or the lower the frequency the greater the (rise in) temperature gains both marks 2 (b) move a thermometer into the infrared region / just beyond the red light allow use an infrared camera / infrared sensor 1 the temperature increases beyond 24( C) accept temperature higher than for the red light 1 (c) v = f λ accept or or accept or allow 1 mark for correct substitution ie = λ 2 (d) at night the surroundings are cooler accept at night the air is colder there is no heat from the Sun is insufficient or at night there is a greater temperature difference between people and surroundings 1 (so surroundings) emit less infrared (than in daytime) accept camera detects a greater contrast Or gives larger difference in infrared emitted (between people and surroundings) 1[9]

7 7.(for both fibres) increasing the wavelength of light decreases and then increases the percentage / amount of light transmitted 1 accept for 1 mark: (for both fibres) increasing the wavelength (of light) to 5 (x 10-7 metres), decreases the (percentage) transmission (for both fibres) the minimum transmission happens at 5 (x 10-7 metres) or maximum transmission occurs at 6.5 (x 10-7 metres) accept for a further 1 mark: (for both fibres) increasing the wavelength of the light from 5 (x 10-7 metres) increases the amount of light transmitted increasing wavelength (of light), decreases the percentage transmitted is insufficient on its own 1 the shorter fibre transmits a greater percentage of light (at the same wavelength) accept for 1 mark: Any statement that correctly processes data to compare the fibres 1 [3] Reflection 1. (a) The diagram shows a ray of light being reflected by a plane mirror. (i) What is a plane mirror? flat mirror or reflector (1) (ii)which of the angles, a, b, c or d, is: the angle of incidence; b the angle of reflection? c (2) (b) The diagram shows a road junction seen from above. A mirror placed at the side of the road allows the driver of car X to see car Y. Using the same mirror symbol given in part (a), draw a plane mirror to show how it should be placed so that the driver of car X can see car Y. (2) [5]

8 2. In the diagram, a frog sits on a rock in a pond.. In the diagram below, a frog sits on a rock in a pond. (a) Complete the following sentences by drawing a ring around the correct line in the box. (i) The frog can see its image in the pond because the surface of the pond acts (1) like a concave convex plane mirror. (ii) Draw a ring around each of two words from the box below to describe the image in the pond. (2) bigger inverted real smaller upright virtual (b) There is an insect underneath the rock. Use a ruler to draw rays of light on the diagram to show how the frog uses reflection to see the insect. Mark the direction of the rays and show where the image of the insect appears to the frog. (3) [6] 3. A ship in front of a cliff sounds one blast of its horn. Later an echo is heard. (a) Choose a word from the list to complete the sentence below: radiation reflection refraction The echo is caused by...reflection...(1) (b)the ship is 1020 metres from the cliff. The echo is heard 6 seconds later. (i) The distance the sound wave travels from the ship to the cliff and back to the ship is 2040 m. (ii) Calculate the speed of the sound wave....v = Speed m/s (2) [4] 4.. When sound waves reach a material, some of the energy of the sound is reflected and some is transmitted through the material. (a) Complete the sentence. Sound waves are caused by...vibrations/oscillations...(1)

9 (b) The graphs J, K, L and M represent the sound energy reflected from a surface. The graphs are all drawn to the same scale. Which graph shows the greatest total sound energy output from the surface? Graph...K... (1) (c) The proportion of the sound energy which is reflected or transmitted depends on the material which receives the sound. A student investigates different materials. The diagram shows how a student sets up her equipment. (i) Using a pencil and ruler to draw on the diagram, show how microphone X receives reflected sound. (2) (ii) The student tests four materials. Each sheet of material is 1 mm thick. This has been glued onto a block of expanded polystyrene. Why does the student use the same size of expanded polystyrene block and the same sound level for each test? Both the size of the block and the sound level may affect the sound level received by the microphone so for a valid test must be controlled (1) (iii) The table shows the readings for the sound Sound level Sound level level transmitted to microphone Y. from transmitted loudspeaker to [A] Which surface material transmits the smallest Surface in microphone proportion of the sound? material arbitrary Y in wood.(1) units arbitrary units [B] What proportion is this?...15/60, 1: paper 39...one quarter or 25%... (1) 60 plaster 18 (d) People living in a flat have very noisy neighbours who are always playing loud music. 60 cloth 31 Suggest one practical idea to reduce the 60 wood 15 amount of noise transmitted into the flat through the walls and explain how your idea will work. practical suggestion 1 appropriate reason / explanation 1 example line / panel the walls with wood / plasterboard / increase the thickness of the plaster (on the walls) (1) (this) will absorb / reflect (back) (most / some of) the sound (1) credit legal suggestions for attempting to limit the noise made by the neighbours example ask the neighbours to make less noise (1) by limiting the time(s) music played (1) do not credit reference to sound particles for second mark (2)[9]

10 Refraction 1. Level 3 (5 6 marks): A detailed and coherent plan covering all the major steps is provided. The steps in the method are logically ordered. The method would lead to the production of valid results. A source of inaccuracy is provided. Level 2 (3 4 marks): The bulk of a method is described with mostly relevant detail. The method may not be in a completely logical sequence and may be missing some detail. Level 1 (1 2 marks): Simple statements are made. The response may lack a logical structure and would not lead to the production of valid results. 0 marks: No relevant content. Indicative content a labelled diagram may cover some points place a glass block on a piece of paper draw around the glass block and then remove from the paper draw a line at 90 to one side of the block (the normal) use a protractor to measure and then draw a line at an angle of 20 to the normal replace the glass block using a ray box and slit point the ray of light down the drawn line mark the ray of light emerging from the block remove the block and draw in the refracted ray measure the angle of refraction with a protractor repeat the procedure for a range of values of the angle of incidence possible source of inaccuracy the width of the light ray which makes it difficult to judge where the centre of the ray is [6] 2. A man is walking along the bank of a river. He sees a fish which seems to be at X. (a) Show, on the diagram, where the fish really is. Complete the ray of light which goes from the fish into the man s eye. (2) (b) Complete the sentence. The ray of light is...refracted... as it passes from the water into the air.(1) [3]

11 3. (a) refraction or refracting 1 (L6) (b) a ray bending towards the normal at the first surface accept a ray that is within the shaded area both sections of the ray must be straight and continuous ignore any arrows an emerging ray bending away from the normal at the second surface accept an emerging ray that is within the shaded area the emergent ray does not have to be parallel to the incident ray 2 (L7) (c) a continuous straight line for ray D ignore any arrows ignore any reflected rays a continuous ray F that bends away from the normal shaded area do not accept an emergent ray that does not refract accept a ray drawn within the 2 (L7)[5] Colour 1. (a) true false for all four correct, award two marks for any two or three correct, award one mark for one correct answer, award no marks if more than one box is ticked in any row, do not give credit for that row 2 (L6)

12 (b) any two from white light is a mixture of colours the red book absorbs all of the colours of light except red accept the other colours are absorbed only red light is reflected red light is reflected is insufficient 2 (L7) (c) What colour does the red book appear? colour of filter red green blue black magenta cyan no filter red filter green filter magenta cyan One mark for each tick 4 (L7)[8] 2. Answers may be in either order (a) it absorbs the green light accept the green light is not reflected 1 it scatters the red and the blue light both colours are required for the mark accept it reflects the red and the blue light accept the eye receives only red and blue light accept it reflects only the red and the blue light or it absorbs only the green light for both marks 1 (b) (i) it is absorbed by the cyan paint do not accept it is absorbed 1 (ii) it is absorbed by the yellow paint do not accept it is absorbed 1 (iii) it is scattered or reflected by both paints accept it is scattered or reflected 1

13 (c) (i) cyan and magenta colours may be in either order 1 (ii) magenta and yellow colours may be in either order 1[7] Sound 1. (a) A student uses two pieces of equipment, A and B, to display a sound wave. (i) Use words from the box to complete the sentence. a loudspeaker a microphone an oscilloscope A is... microphone... and B is... an oscilloscope....(2) (ii) Use words from the box to complete the sentence. the amplitude half the amplitude the frequency half the frequency The distance x marked on the diagram measures... the amplitude... of the sound wave.(1) (iii) Complete the sentence:the distance x becomes smaller. This is because the sound has become...quieter...(1) (b) There is no air in space. Astronauts in space cannot hear sounds from outside their spacesuits. Explain this....no ( air) particles in space......vibrations are passed from particles to neighbouring particle for sound to travel (2) [6] 2. Most young people can hear sounds in the frequency range 20 Hz to Hz. (a) Tick the box beside the statement which best describes frequency. the maximum disturbance caused by a wave the number of complete vibrations per second the distance between one crest of a wave and the next one the distance travelled by a wave in 1 second (1) (b) Diagram X shows a trace on an oscilloscope screen.

14 #(i) Draw a trace on diagram Y which has a higher frequency than but same amplitude as.that shown in diagram X. (ii) Draw a trace on diagram Z which has a larger amplitude than but same frequency as that shown in diagram X. (2) (c) Choose words from the list below to complete the following sentences. higher louder lower quieter (i) A musical note with a high frequency sounds...higher (pitched)... than one with a low frequency. (ii) A noise of small amplitude sounds...quieter... than one with large amplitude.(2) 7. The diagram shows four oscilloscope wave traces. The controls of the oscilloscope were the same for each wave trace. Which one of the waves traces, A, B, C or D, has: [5] (i) the largest amplitude,...b...(1) (ii) the lowest frequency?...a...(1) (Total 2 marks) Ultrasound 1. (a)(sound waves) which have a frequency higher than the upper limit of hearing for humans or a (sound) wave (of frequency) above Hz 1 sound waves that cannot be heard is insufficient a wave of frequency Hz is insufficient (b) an answer of 1280 gains 2 marks allow 2 marks for the correct substitution ie provided no subsequent step

15 allow 2 marks for the substitution provided no subsequent step allow 1 mark for the substitution provided no subsequent step allow 1 mark for the identification that time (boat to bed) is 0.4 (c) any one from: pre-natal scanning / imaging imaging of a named organ (that is not surrounded by bone), eg stomach, bladder, testicles accept heart do not allow brain or lungs (either of these negates a correct answer) Doppler scanning blood flow 1 [5] 2 (a) (i) 1/3 of s = (33)s 1 (ii) Hz or their (a)(i) correctly calculated 1 (iii) any two from: frequency is above (Hz) frequency is above the upper limit of audible range upper limit of audible range equals (Hz) ignore reference to lower limit it is ultrasound/ultrasonic 2 (b) (i) wave (partially) reflected 1 at crack to produce A and end of bolt to produce B accept at both ends of the crack 1 (ii) (m) allow 2 marks for time = allow 1 mark for time = answers 0.15 or or 0.09 gain 2 marks answers 0.18 or 0.03 gain 1 mark the unit is not required but if given must be consistent with numerical answer for the available marks 3[9] Seismic 1. The diagram shows the passage of P waves, created by an earthquake, through the earth. (a) Label the layers of the earth (4) A inner or solid core B outer or liquid core C mantle D crust (b) What name is given to the wave effect which causes the P waves to change direction as the travel towards the core? refraction...(1) A C B D

16 (c) What causes the change in direction? 1 mark change in speed (due to change in density).. for 2 marks, the deeper the wave goes (the higher the density) and the faster the wave travels.(2) (d) S waves are also created by the earth quake. Give two differences between S and P waves. Two from: S transverse, P longitudinal S travel slower than P P travels through liquids which S does not (2) (e) sketch the passage of S waves through the earth on the second diagram from the same epicentre (2) 1 mark for shape of refraction similar to P waves 1 mark for shadow zone (size and position approximately correct eg about ½ of circumference of earth on opposite side) (f)explain why there is a shadow region on the opposite side of the earth to the epicentre, where no S waves are received. S waves are unable to pass into liquid outer core (1)[8] 2. The vibration caused by a P wave travelling at 7.6 km/s has been recorded on a seismic chart. (i) How many waves are produced in one second?...5 in 10 s (1) (ii) Calculate the wavelength of the P wave. Show clearly how you work out your answer and give the unit km/s = 7600 m/s... λ=v.= f Wavelength = m (15.2 km)...(2) [4] Blackbody Radiation 1. (a) convection any four for 1 mark each air is heated by the burner / particles gain energy air expands / particles move about more / particles move faster air becomes less dense / particles are more spread out air rises / particles rise not heat rises air from C moves into the heater / particles from C move into the heater toreplace it / them 4