polarization is a property of one type of wave....polarization is a property of one type of wave....

Polarization is a property of one type of wave.

(a) Circle below the type of wave that can be polarized.

transverse longitudinal

(1)

1

(b) Give one example of the type of wave that can be polarized.

___________________________________________________________________

(1)

(c) Explain why some waves can be polarized but others cannot. Space is provided forsketches should you wish to include them in your answer.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)

(Total 5 marks)

of 43St Bede's Catholic Comprehensive School and Byron College

The graph in Figure 1 shows the results of an investigation of how the visible light intensityI varies with distance d from a filament lamp. The lamp can be assumed to behave as a pointsource of light.

Figure 1

(a) Use data from the graph to show that the visible light intensity varies with distanceaccording to an inverse square law.

(3)

2

(b) Find the power of the visible light emitted by the filament lamp.

power ____________________

(2)

(Total 5 marks)


The diagram below is an arrangement for analysing the light emitted by a source.

3

(a) Suggest a light source that would emit a continuous spectrum.

___________________________________________________________________

(1)

(b) The light source emits a range of wavelengths from 500 nm to 700 nm. The light is incidenton a diffraction grating that has 10 000 lines per metre.

(i) Calculate the angle from the straight through direction at which the first ordermaximum for the 500 nm wavelength is formed.

Angle = ____________________

(3)

(ii) Calculate the angular width of the first order spectrum.

Angular width ____________________

(1)

(iii) The detector is positioned 2.0 m from the grating. Calculate the distance between theextreme ends of the first order spectrum in this position.

Distance = ____________________

(1)

(c) The single slit is initially illuminated by light from a point source that is 0.02 m from the slit.

State and explain how the intensity of light incident on the single slit changes when the lightsource is moved to a position 0.05 m from the slit.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(4)

(Total 10 marks)


(a) State the difference between transverse and longitudinal waves.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

4

(b) State what is meant by polarisation.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

(c) Explain why polarisation can be used to distinguish between transverse and longitudinalwaves.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

(Total 6 marks)


The equation for the speed, v, of a transverse wave along a stretched string is:

where T is the tension in the string and μ is the mass per unit length of the string.

(a) State the quantities that would need to be measured in order to calculate a single value forthe speed of the wave using the equation. Name a suitable measuring instrument for eachquantity.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(4)

5

(b) The apparatus shown in the diagram below could be used to measure a value for v.

Explain how this apparatus may be used to calculate an accurate value of the speed of thetransverse wave along the string.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(4)


(c) With the signal generator in the diagram below set at 152 Hz, 10 loops fit the vibratinglength of the string exactly. The string is of length 2.0 m and the mass on the end of it is0.72 kg.

the Earth’s gravitation field strength, g = 9.8 N kg–1

Calculate the mass of the string.

Mass = ____________________

(5)

(Total 13 marks)

The intensity of a sound is 1.9 × 10–8 W m–2 at a distance of 0.25 km from the source. Calculatethe intensity of the sound at a distance of 0.75 km from the source.

Intensity of sound ____________________

(Total 3 marks)

6

Short pulses of sound are reflected from the wall of a building 18 m away from the sound source.The reflected pulses return to the source after 0.11 s.

(a) Calculate the speed of sound.

Speed of sound ____________________

(3)

7

(b) The sound source now emits a continuous tone at a constant frequency. An observer,walking at a constant speed from the source to the wall, hears a regular rise and fall in theintensity of the sound. Explain how the minima of intensity occur.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)

(Total 6 marks)


Figure 1 shows a stretched string driven by a vibrator. The right-hand end of the string is fixed toa wall. A stationary wave is produced on the string; the string vibrates in two loops.

Figure 1

8

(a) State the physical conditions that are necessary for a stationary wave to form on the string.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)

(b) Explain how you know that the wave on the string is transverse.

___________________________________________________________________

(1)

(c) Compare the amplitude and phase of the oscillations of points A and B on the string.

Amplitude __________________________________________________________

Phase _____________________________________________________________

(2)


(d) The length of the string is 1.2 m and the speed of the transverse wave on the string is6.2 m s–1.

Calculate the vibration frequency of the vibrator.

Vibration frequency ____________________

(3)

(e) The frequency of the vibrator is tripled.

Sketch the new shape of the stationary wave on Figure 2.

Figure 2

(ii) Show on your diagram three points P, Q and R that oscillate in phase.

(2)

(Total 11 marks)


The diagram below shows three wavefronts of light directed towards a glass block in the air. Thedirection of travel of these wavefronts is also shown.

Complete the diagram to show the position of these three wavefronts after partial reflection andrefraction at the surface of the glass block.

(Total 3 marks)

9

(a) Figure 1 shows how the displacement s of the particles in a medium carrying a pulse ofultrasound varies with distance d along the medium at one instant.

Figure 1

(i) State the amplitude of the wave.

______________________________________________________________

(1)

10


(ii) The speed of the wave is 1200 m s–1. Calculate the frequency of oscillation of theparticles of the medium when the ultrasound wave is travelling through it.

Frequency of oscillation ____________________

(3)

(b) An ultrasound transmitter is placed directly on the skin of a patient. Figure 2 shows theamplitudes of the transmitted pulse and the pulse received after reflection by an organ inthe body. amplitude

Figure 2

(i) Give two possible reasons why the amplitude of the received pulse is lower than thatwhich is transmitted.

Reason 1 _____________________________________________________

______________________________________________________________

Reason 2 _____________________________________________________

______________________________________________________________

(2)

(ii) The speed of ultrasound in body tissue is 1200 m s–1. Calculate the depth of thereflecting surface below the skin.

Depth of reflecting surface ____________________

(2)

(Total 8 marks)


A square metre of the Moon’s surface that is perpendicular to sunlight receives 1.4 kJ of energyevery second from the Sun. Estimate the total energy radiated by the Sun every secondassuming that the Sun acts as a point source.

mean distance of the Moon from the Sun = 1.5 × 1011 m

Total energy radiated ____________________

(Total 3 marks)

11

The diagram below shows a hammer being struck against the end of a horizontal metal rod. Apulse of sound travels along the rod from where the hammer strikes it to the far end and backagain. The sound pulse throws the hammer and rod apart when it returns. An electrical timingcircuit measures the time for which the hammer and the rod are in contact.

12

(a) Circle the word below that describes the type of wave that travels along the rod.

transverse longitudinal

(1)

(b) State the name of the effect that causes the sound pulse to return to the hammer.

___________________________________________________________________

(1)


(c) The rod is 0.45 m long and the time for which the hammer is in contact with the rod is1.6 × 10–4 s. Calculate the speed of sound in the rod.

Speed of sound ____________________

(3)

(Total 5 marks)

State two factors that affect the fundamental frequency of a vibrating stretched string.

Factor 1 ___________________________________

Factor 2 ___________________________________

(Total 2 marks)

13

(a) State the conditions necessary for a stationary wave to be produced.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)

14


(b) The diagram shows a stationary wave on a stretched guitar string of length 0.62 m.

The speed of transverse waves along the string is 320 m s–1. Calculate the frequency ofthe note being played.

Frequency ____________________

(3)

(Total 6 marks)

(a) With the aid of a clearly labelled diagram explain how a sound wave in air transmits energyaway from its source.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)

15


(b) Unlike sound waves, transverse waves can be polarised. Give one example of atransverse wave and draw a diagram to show how it can be plane polarised. State amethod of polarising a wave of the type you have chosen.

Example transverse wave ____________________

Method of polarisation ____________________

(3)

(Total 6 marks)

Figure 1 shows a violin string. One way to produce a musical note is to pull the centre of thestring to one side and then release it quickly.

Figure 1

(a) Draw on Figure 1 the fundamental standing wave that will appear on the string when thenote is sounding.

(1)

16

(b) (i) Sketch on Figure 2 the standing wave that corresponds to a frequency of three timesthat of the fundamental.

Figure 2


(ii) State the name given to points on the standing wave where there is no vibration ofthe string.

______________________________________________________________

(2)

(c) Children often learn to play the violin on a small instrument with shorter strings. Theseshorter strings have to produce the same fundamental frequencies as those on the full-sizeinstrument. State two ways in which this can be achieved.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

(Total 5 marks)

Figure 1 shows the displacement of particles in an ultrasound wave at different distances fromthe source at a particular time. The wave travels at 3200 m s–1.

Figure 1

(a) (i) Use the graph to find the wavelength of the wave in Figure 1.

wavelength ____________________

17


(ii) Calculate the frequency of the ultrasound wave.

frequency ____________________

(3)

(b) One industrial use for ultrasound waves is to detect flaws inside a metal block. Figure 2ashows the arrangement in which the waves are fired downwards in short pulses from atransmitter. Figure 2b shows the amplitudes of the initial pulse and the reflected signalsrecorded by the receiver. You may assume that there is no reflected pulse received fromthe upper surface of the block.

Figure 2a


Figure 2b

The ultrasound wave travels at 3200 m s–1. Use data from Figure 2b to calculate thedistance of the flaw below the top of the block.

distance ____________________

(3)

(Total 6 marks)

(a) Explain how a stationary wave is produced when a stretched string is plucked.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)

18


(b) (i) On Figure 1, draw the fundamental mode of vibration of a stretched string. Label anynodes with a letter N and any antinodes with a letter A.

Figure 1

(2)

(ii) On Figure 2, draw the fourth harmonic (third overtone) for the stretched string. Labelany nodes with a letter N and any antinodes with a letter A.

Figure 2

(2)

(c) The fundamental frequency of vibration, f, of a string is given by:

where T = the tension in the string l = the length of the string µ = the mass per unit length of the string

A string has a tension of 180 N and a length of 0.70 m.

(i) What would need to be done to the length of the string in order to double thefrequency?

______________________________________________________________

(1)

f =

(ii) What would need to be done to the tension of the string in order to double thefrequency?

______________________________________________________________

(2)

(Total 10 marks)


Which one of the following statements about stationary waves is true?

A Particles between adjacent nodes all have the same amplitude.

B Particles between adjacent nodes are out of phase with each other.

C Particles immediately on either side of a node are moving in opposite directions.

D There is minimum disturbance of the medium at an antinode.

(Total 1 mark)

19

The figure below shows a graph of displacement against time for two waves A and B. Thesewaves meet in phase and add to form a resultant wave.

(a) State the amplitude of the resultant wave

___________________________________________________________________

(1)

20

(b) Calculate the ratio

intensity of wave B : intensity of wave A.

(2)

(Total 3 marks)


Which one of the following types of wave cannot be polarised?

A radio

B ultrasonic

C microwave

D ultraviolet

(Total 1 mark)

21

The figure below shows the appearance of a stationary wave on a stretched string at one instantin time. In the position shown each part of the string has its maximum displacement. The arrow atW shows the direction in which the point W is about to move.

(a) (i) Mark clearly on the diagram the directions in which points X, Y and Z are about to move.

22

(ii) State the conditions necessary for a stationary wave to be produced on the string.

______________________________________________________________

______________________________________________________________

(4)

(b) In the figure above, the frequency of vibration is 120 Hz. Calculate the frequency of thefundamental vibration for this string.

frequency of the fundamental vibration ____________________

(2)

(Total 6 marks)


The least distance between two points of a progressive transverse wave which have a phase

difference of rad is 0.050 m. If the frequency of the wave is 500 Hz, what is the speed of thewave?

A 25 m s–1

B 75 m s–1

C 150 m s–1

D 1666 m s–1

(Total 1 mark)

23

Explain the differences between an undamped progressive transverse wave and a stationarytransverse wave, in terms of (a) amplitude, (b) phase and (c) energy transfer.

(a) amplitude

progressive wave ____________________________________________________

___________________________________________________________________

stationary wave ______________________________________________________

___________________________________________________________________

24

(b) phase


___________________________________________________________________

stationary wave ______________________________________________________

___________________________________________________________________

(c) energy transfer


___________________________________________________________________

stationary wave ______________________________________________________

___________________________________________________________________

(Total 5 marks)

The graph shows the variation of displacement of the particles with distance along a stationary

transverse wave at time t = 0 when the displacement of the particles is greatest. The period ofthe vibrations causing the wave is 0.040 s.

25


(a) Using the same axes,

(i) draw the appearance of the wave at t = 0.010 s, labelling this graph B,

(ii) draw the appearance of the wave at t = 0.020 s, labelling this graph C,

(iii) show an antinode labelled A and a node labelled N.

(3)

(b) (i) Describe the motion of the particle at V, giving its frequency and amplitude.

______________________________________________________________

______________________________________________________________

(ii) State the amplitude of the particle at W and its phase relations with the particle at Vand the particle at Z.

______________________________________________________________

______________________________________________________________

______________________________________________________________

(6)

(Total 9 marks)

Which one of the following statements about stationary waves is true?

A Particles between adjacent nodes all have the same amplitude.

B Particles between adjacent nodes are out of phase with each other.

C Particles immediately on either side of a node are moving in opposite directions.

D There is a minimum disturbance of the medium at an antinode.

(Total 1 mark)

26


(a) For a sound wave travelling through air, explain what is meant by particle displacement,amplitude and wavelength.

Particle displacement _________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

amplitude __________________________________________________________

___________________________________________________________________

___________________________________________________________________

wavelength _________________________________________________________

___________________________________________________________________

___________________________________________________________________

(4)

27

(b)

Graph A shows the variation of particle displacement with time at a point on the path of aprogressive wave of constant amplitude.

Graph B shows the variation of particle displacement with distance along the same waveat a particular instant.

(i) Show on graph A

(1) the wave amplitude, a,

(2) the period, T, of the vibrations providing the wave.


(ii) Show on graph B

(1) the wavelength of the wave, λ,

(2) two points, P and Q, which are always π/2 out of phase.

(4)

(Total 8 marks)

28

frequency of vibration = 50 Hz

The diagram above shows a stationary wave on a stretched string at a time t = 0. Which one of

the diagrams, A to D, correctly shows the position of the string at a time t = 0.010 s?

A

B

C

D

(Total 1 mark)

A progressive wave in a stretched string has a speed of 20 m s−1 and a frequency of 100 Hz.What is the phase difference between two points 25 mm apart?

29

A zero

B rad

C rad

D π rad

(Total 1 mark)


The audible range of a girl's hearing is 30 Hz to 16 500 Hz. If the speed of sound in air is 330 ms−1, what is the shortest wavelength of sound in air which the girl can hear?

A m

B m

C m

D m(Total 1 mark)

30

Which one of the following types of wave cannot be polarised?

A radio

B ultraviolet

C microwave

D ultrasonic

(Total 1 mark)

31

A wave motion has period T, frequency f, wavelength λ and speed ʋ. Which one of the followingequations is incorrect?

32

A 1 = Tf

B T =

C λ =

D Tʋ = λ(Total 1 mark)

(a) The diagram shows the apparatus required for a simple experiment to measure the speedof sound.

33


A pulse of sound is sent down a hollow glass tube and is reflected at the sealed end of thetube. A microphone, M, placed at the open end detects the initial pulse and, at a later time,the reflected pulse. The microphone is connected to an oscilloscope which gives a signalwhen the microphone detects a pulse of sound.

The signal displayed on the oscilloscope screen is shown below.

If the time base of the oscilloscope is set to 2.0 ms per division, estimate the speed ofsound in air.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)


(b) Describe how the frequency of a sinusoidal alternating (ac) voltage source is measuredusing an oscilloscope.

Your answer should include a sketch of the trace seen on the oscilloscope screen andexplain how the frequency is obtained from this trace.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(5)

(Total 8 marks)

A uniform wire fixed at both ends is vibrating in its fundamental mode. Which one of the followingstatements is not correct for all the vibrating particles?

A They vibrate in phase.

B They vibrate with the same amplitude.

C They vibrate with the same frequency.

D They vibrate at right angles to the wire.

(Total 1 mark)

34


Figure 1 shows three particles in a medium that is transmitting a sound wave. Particles A and Care separated by one wavelength and particle B is half way between them when no sound isbeing transmitted.

Figure 1

(a) Name the type of wave that is involved in the transmission of this sound.

___________________________________________________________________

(1)

35

(b) At one instant particle A is displaced to the point A' indicated by the tip of the arrow inFigure 1. Show on Figure 1 the displacements of particles B and C at the same instant.Label the position B' and C' respectively.

(1)

(c) Explain briefly how energy is transmitted in this sound wave.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(2)

(Total 4 marks)


Mark schemes

(a) TransverseB11

(b) correct example of transverse wave( e.g. light / electromagnetic / radio etc. allow photon b.o.d.)

B1

(c) [transverse] displacement vector perpendicular to energydirection [accept ‘direction of motion’]

B1

[longitudinal] vector parallel to energy directionB1

polarisation is restriction of displacement vector to oneplane OWTTE

[allow any or all marks on clear diagram]B1

[5]


(a) Statement that Id2 (or Ir2) should be constant

C1

Calculation of Id2 for two corresponding values of I and d

C1

Calculation of Id2 for three corresponding values of I and dwith conclusion

A13

orwork out constant for one set

C1

Calculate intensity for 1 new distance

C1

Calculate intensity for 2 new distances and compares withgraph.

A1

orReads one value from graph and calculates value for doubledistance

C1

Explains that this is ¼ original intensity

C1

Does this twice with conclusion

A1

(b) I = P/4πd2 or substitution of two corresponding values of Iand d

C1

0.40 W (condone 1sf)

A12

[5]

2


(a) filament lamp / sun etc.B1

(1)

3

(b) (i) d = 1.0 × 10–4 mC1

use of λ = dsin θ or substituted valuesC1

θ1 = 0.286° / 0.29°A1

(3)

(ii) Δθ = 0.115° (c.a.o.)B1

(1)

(iii) width = 4.0 × 10–3 m or 3.9 × 10–3 m (e.c.f. for 2 × sin (b(ii))or 2 × tan (b(ii)); allow 1 s.f.)

B1(1)

(c) lower intensityC1

because energy spreadsC1

use or statement of inverse square lawC1

ratio 0.16 or falls by factor of 6.25 c.a.o.A1

(4)

[10]

(a) transverse: vibration / displacement / disturbance not movement isperpendicular to direction of travel

B1

longitudinal: vibration / displacement / disturbance not movementis parallel to (same) direction of travel

B1

C1 for idea of transverse and longitudinal being perpendicular(2)

4

(b) restriction of vibration / idea of how polarisation occursB1

single plane / same orientation – diagram may helpB1

(2)


(c) only transverse can be polarised / longitudinal cannotB1

idea of being able to restrict vibration to single planeor longitudinal not being perpendicular to motionor longitudinal vibrating in direction of travel

B1(2)

[6]

(a) tension – newtonmeterB2

or tension – from mass on balanceB1

and – multiply by gB1

mass – balance / scalesB1

length – rule / tape / rulerB1

(4)

5

(b) frequency read from signal generator when standing wave produced / use of strobeetc.

B1

measure λ using several loops or full length of stringB1

node → node / each loop = λ / 2B1

use of c = fλB1

(4)

(c) λ = 0.40 (m)C1

c = 60.8 (m s–1) e.c.f. from λC1

T = 7.06 (N)C1

μ = 1.9(1) × 10–3 (kg m–1) c.a.o.A1

m = 2 × μ value (= 3.8 × 10–3 kg or equivalent unit) e.c.f. s.f.p. applied only at thisanswer

B1(5)

[13]

use of inverse-square lawC1

3 × distance so 1 / 9 × intensity (or equivalent calc)C1

1.9 × 10–8 / 9 = 2.11 × 10–9 Wm–2

A1

[3]

6


(a) distance travelled = 2 × 18 mC1

Speed = 36 / 0.11M1

= 327 m / s [164 m / s scores 2]A1

7

(b) mention of standing waves or superposition or interferenceB1

mention of two waves, opposite directionsB1

because they are permanently out of phase, permanentlydestructively interfere, permanently in antiphase

B1

[6]

(a) Reflection implied /2 waves in opposite directions/fixedend (not ends)

B1

Similar amplitude/little energy loss at wall

B1

frequency constant or same frequency/wavelength or correctwavelength condition specified

B13

8

(b) displacement perpendicular to rest/average/mean positionof stringor string displacement perpendicular to energy propagationdirection OWTTE

B11

(c) A larger than B

B1

A180° /π out of phase with B OWTTE

B12


(d) λ = 1.2

B1

c = f λ; allow e.c.f. from wrong λ

M1

f = 6.2/1.2 = 5.2 Hz

A13

(e) (i) diagram correct (6 loops)

B11

(ii) Q and R correctly in phase with P; must be aposition where vt occurs

B11

[11]

reflection wavefront direction sensible

B1refraction wavefront direction sensible

B1one pair of wavefronts correctly spaced

B1

[3]

9

(a) (i) 2(.0) × 10–5 m (i.e. allow 1 sf)

B11

(ii) λ = 4(.0) × 10–4 (m)

B1

v = fλ (condone c = fλ)

C1

3.0 MHz sf penalty appliesallow e.c.f. for omitting 10–4 (300 Hz) but sf penaltyapplies for e.g. 0.3 kHz)

A13

10


(b) (i) ultrasound/wave/pulse/energy spreads out fromthe transmitter (beam not uni-directional)

B1

energy is absorbed by(or lost to) the transmittingmedium/tissue/body

B1

incident ultrasound/wave/pulse/energy is not allreflected (by the reflecting object)

or some is transmitted /absorbed by the organor is reflected at different angles (so does not returnto detector)

B1

some ultrasound/wave/pulse/energy reflected by theskin since gel was not used

B1max2

ANY 2

(ii) distance travelled 1200 × 95 or 114 000 or 0.114 m(i.e. mark for use of velocity × time ignoring powersof 10)

C1

0.057 m ( allow answers in range 0.055 to 0.057 )

A12

[8]

use of r2

C1

P = 1.4 × 103 × 4 × 3.14 × (1.5 × 1011)2

C1

= 3.96 × 1026 W

A1

[3]

11


(a) longitudinal

B1

(b) reflection

B1

(c) use of speed = distance/time

C1

(0.45 or 0.9)/1.6 × 10–4 or 0.45/0.8 × 10–4

C1

= 5.6 km s-1 [5.625] A1

[5]

12

Two of

B1

Mass or mass/unit length

B1

TensionLengthTemperature

[2]

13

(a) superposition (of progressive waves)

B1

incident wave and reflected wave/wave reflected through180O/waves travelling in opposite directions

B1

same frequency/wavelength

B1

in same medium.

B1

Any 3 out of 4 points3

14


(b) f = c/λ

C1

λ = 1.24

C1

f = 258 Hz

A1

e.g. f = 512 gets 1 mark3

[6]

(a) Good diagram of pressure variations/particle oscillationswith at least one label indicating direction of propagation,pressure variation or density variation

B1

Plus any two from five ofVibrating source

B1

Energy transferred to (air) molecules

B1

Energy passed on by collisions between molecules

B1

Oscillations of air molecule neighbours slightly outof phase

B1

Oscillations/waves are longitudinal/energy transfer parallelto vibrations

B13

15


(b) Diagram showing several transverse vibrations/waves which aresubsequently limited to one after polarisation

B1

Valid example (light, microwaves etc.)

accept sunlightSuitable polariser for the stated example

M1

(polaroid, reflection, metal grid etc). Not sunglasses

A13

[6]

(a) single loop/half of sine wave shown between fixed points

B11

16

(b) (i) 3 loops shown

B1

(ii) node

B12

(c) greater mass per unit length of string/thicker string

B1

less tension/loosen string/slacken string

B12

[5]

(a) (i) wavelength read-off = 1.2 mm

B1

17

(ii) 3200/1.2 × 10-3 ecf from (a) (i)

C13

2.7 MHz

A1


(b) read-off correct 1.3 µs

C1

factor of two correct

C13

= 2.1 × 10-3 m [2.08] c.a.o.

A1

[6]

(a) idea that there are waves in opposite directions

B1

because of reflection at end of string

B1

the two waves interfere with each other/superimpose

B13

18

(b) (i) one loop

M1

with N at each end and A in the middle

A12

(ii) 4 approximately even loops

B1

all nodes and antinodes correctly marked for theirnumber of loops

B12


(c) (i) length halved/0.35 (m)

B11

(ii) tension greater

C1

T = 720 (N)/increased by a factor of 4

A12

[10]

C

[1]19

(a) 4 mm

B11

(b) 3:1; 3/1

C1

9 or 9:1

A12

[3]

20

B

[1]21

(a) (i) Z down

B1

X and Y up

B1

(ii) any two of:

same frequency/wavelength not ‘it has same frequency’moving in opposite directions,reflected at end of string,same/similar amplitudeinteger no of ½ wavelengths between walls

B24

22


(b) indicates f is 3 times fundamental in some way or thatlength is 3λ/2

C1

40 Hz

A12

[6]

C

[1]23

amplitude: each point along wave (1)

has same amplitude for progressive wavebut varies for stationary wave (1)

phase: progressive wave, adjacent points vibrate with different phase (1)stationary wave, between nodes all particles vibrate in phase[or there are only two phases] (1)

energy transfer: progressive wave, energy is transferred through space (1)stationary wave, energy is not transferred through space (1)

[5]

24

(a) (i) B line along distance axis (1)25(ii) C negative sine wave starting at O (1)

(iii) A, N (1)(3)

(b) (i) s.h.m. [or particle stationary] (1)amplitude = 20 mm (1)

= 25 Hz or s–1 (1)

(ii) 10 mm (1)W, V phase difference π [or antiphase or 180°] (1)W, Z in phase (1)

(6)

[9]

C

[1]26


(a) (i) displacement is distance of particle (1)

from mean [or equilibrium] position (1)

in direction of wave (energy) (1)

amplitude is maximum displacement (1)

wavelength is shortest distance (1)

between two points in phase (1)(max 4)

27

(b)

any two points apart (1)(4)

[8]

C

[1]28

B

[1]29

C

[1]30

D

[1]31


B

[1]32

(a) time elapsed = 8.5 ± 0.2 (ms) (1)distance travelled = 3 (m) (1) (allow C.E. if d = 1.5 (m))

speed of sound = = 350 m s–1 (353) (1)3

33

(b) connect oscilloscope across ac source (or diagram or ac to Y plates) (1)adjust time base to give trace (1)adjust voltage sensitivity (1)sinusoidal trace shown (1)how to measure T from trace (1)

max 5

[8]

B

[1]34

(a) longitudinal wave

B11

(b) arrows showing B displaced to the left and C to the right

B11

35

(c) particles in the transmitting medium are made to vibrate/givenenergy

B1

ormention of a compression/region of increased pressure (orrarefaction)cause nearby particles to vibrate/have energy/move

B1

orthe compression produces a compression further along (themedium)

2

[4]


polarization is a property of one type of wave....polarization is a property of one type of wave....

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