Diffraction
8.2What the syllabus asks of you
- explain the meaning of the term diffraction
- show an understanding of experiments that demonstrate diffraction including the qualitative effect of the gap width relative to the wavelength of the wave; for example diffraction of water waves in a ripple tank
Read the notes first
Chapter 8: Diffraction
Drill this topic
Every question on Diffraction, untimed, marked as you go.
Make a worksheet
Choose the years and how many questions, then print it with the answers on separate pages.
59 questions
1May / June 2026 · Paper 11 · Q28Show mark scheme →
Aθ decreases, wavelength remains the same
Bθ increases, wavelength remains the same
Cθ remains the same, wavelength decreases
Dθ remains the same, wavelength increases
Mark scheme
2May / June 2026 · Paper 12 · Q26Show mark scheme →
Awavelength 10^-1 m, gap width 10^0 m
Bwavelength 10^-1 m, gap width 10^-2 m
Cwavelength 10^0 m, gap width 10^0 m
Dwavelength 10^0 m, gap width 10^2 m
Mark scheme
3Oct / Nov 2025 · Paper 12 · Q28Show mark scheme →
Afrequency decreases, speed increases
Bfrequency increases, speed decreases
Cfrequency no change, speed decreases
Dfrequency no change, speed no change
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4Oct / Nov 2025 · Paper 14 · Q26Show mark scheme →
Athe change in observed frequency of a wave due to a movement of the wave source
Bthe spreading of a wave as it passes through a gap or around an obstacle
Cwhen oscillations of a wave are confined to one plane
Dthe resultant displacement of two waves is equal to the sum of the displacements of the individual waves when the waves meet
Mark scheme
5May / June 2025 · Paper 13 · Q30Show mark scheme →
A[diagram A: plane waves before barrier, short straight wavelets after narrow gap]
B[diagram B: plane waves before barrier, slightly curved wavelets after gap]
C[diagram C: plane waves before barrier, circular wavelets spreading after gap]
D[diagram D: plane waves before barrier, wide circular wavelets spreading after gap]
Mark scheme
6May / June 2025 · Paper 14 · Q26Show mark scheme →
Adiffraction
Binterference
Cpolarisation
Dreflection
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7Feb / March 2025 · Paper 12 · Q28Show mark scheme →
Adecreases / decreases
Bdecreases / increases
Cincreases / decreases
Dincreases / increases
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8Oct / Nov 2024 · Paper 12 · Q29Show mark scheme →
ADecrease the frequency of the wave.
BDecrease the time period of the wave.
CDecrease the width of the slit.
DIncrease the wavelength of the wave.
Mark scheme
9Oct / Nov 2024 · Paper 13 · Q30Show mark scheme →
Adecreasing the distance between the bar and the gap
Bdecreasing the frequency of the wave
Cincreasing the amplitude of the wave
Dincreasing the width of the gap
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10May / June 2024 · Paper 12 · Q22Show mark scheme →
A2.4 × 10⁻³ Hz
B8.0 × 10⁻¹ Hz
C2.7 × 10² Hz
D4.3 × 10² Hz
Mark scheme
11May / June 2024 · Paper 13 · Q28Show mark scheme →
A1 m
B2 m
C4 m
D8 m
Mark scheme
12Oct / Nov 2023 · Paper 11 · Q27Show mark scheme →
AIncrease the amplitude of the waves.
BIncrease the frequency of the waves.
CIncrease the wavelength of the waves.
DIncrease the width of the gap.
Mark scheme
13Oct / Nov 2023 · Paper 12 · Q27Show mark scheme →
Aa long spring
Ba ripple tank
Ca rope
Da stretched string
Mark scheme
14Oct / Nov 2023 · Paper 13 · Q27Show mark scheme →
ADiagram A
BDiagram B
CDiagram C
DDiagram D
Mark scheme
15May / June 2023 · Paper 11 · Q27Show mark scheme →
Adouble the amplitude of the ripples
Bdouble the width of the gap
Chalve the frequency of the ripples
Dhalve the wavelength of the ripples
Mark scheme
16May / June 2023 · Paper 12 · Q27Show mark scheme →
Aa small decrease in the wavelength of the wave
Ba small decrease in the width of the gap
Ca small increase in the frequency of the wave
Da small increase in the height of the barrier
Mark scheme
17May / June 2023 · Paper 13 · Q27Show mark scheme →
A0.5w
Bw
C2w
D4w
Mark scheme
18Feb / March 2023 · Paper 12 · Q27Show mark scheme →
AThe radio waves are coherent but the microwaves are not.
BThe radio waves are diffracted around the mountain but the microwaves are not.
CThe radio waves are reflected by the mountain but the microwaves are not.
DThe radio waves travel at the speed of light but the microwaves do not.
Mark scheme
19Oct / Nov 2022 · Paper 11 · Q28Show mark scheme →
ALess diffraction is observed.
BMore diffraction is observed.
CThere is no diffraction.
DThe same amount of diffraction is observed.
Mark scheme
20Oct / Nov 2022 · Paper 12 · Q28Show mark scheme →
AA wave bounces back from a surface.
BA wave passes from one medium into another.
CA wave passes through a gap in a barrier.
DWaves from two identical sources are superposed.
Mark scheme
21Oct / Nov 2022 · Paper 13 · Q27Show mark scheme →
ADouble the amplitude of the sound wave.
BDouble the width of the doorway.
CHalve the frequency of the sound wave.
DHalve the period of the sound wave.
Mark scheme
22May / June 2022 · Paper 11 · Q28Show mark scheme →
Aθ decreases, wavelength remains the same
Bθ increases, wavelength remains the same
Cθ remains the same, wavelength decreases
Dθ remains the same, wavelength increases
Mark scheme
23May / June 2022 · Paper 12 · Q28Show mark scheme →
Avibration frequency f/2, gap width x/2
Bvibration frequency f/2, gap width 2x
Cvibration frequency 2f, gap width x/2
Dvibration frequency 2f, gap width 2x
Mark scheme
24May / June 2022 · Paper 13 · Q29Show mark scheme →
ADiagram A
BDiagram B
CDiagram C
DDiagram D
Mark scheme
25Feb / March 2022 · Paper 12 · Q26Show mark scheme →
Agap width ½d, wavelength ½λ
Bgap width ½d, wavelength 2λ
Cgap width 2d, wavelength ½λ
Dgap width 2d, wavelength 2λ
Mark scheme
26Oct / Nov 2021 · Paper 11 · Q27Show mark scheme →
Athe amplitude and frequency of the incident wave
Bthe amplitude of the incident wave and the width of the gap
Cthe wavelength and amplitude of the incident wave
Dthe wavelength of the incident wave and the width of the gap
Mark scheme
27Oct / Nov 2021 · Paper 12 · Q28Show mark scheme →
AA single small dot
BA horizontal line
CA vertical line
DA large circle
Mark scheme
28Oct / Nov 2021 · Paper 13 · Q28Show mark scheme →
ADiagram A
BDiagram B
CDiagram C
DDiagram D
Mark scheme
29May / June 2021 · Paper 11 · Q27Show mark scheme →
Adiffraction
BDoppler shift
Cinterference
Dsuperposition
Mark scheme
30May / June 2021 · Paper 12 · Q27Show mark scheme →
ADiagram A
BDiagram B
CDiagram C
DDiagram D
Mark scheme
31May / June 2021 · Paper 13 · Q28Show mark scheme →
A1.3 mm
B750 mm
C7.5 m
D17 m
Mark scheme
32Feb / March 2021 · Paper 12 · Q27Show mark scheme →
Athe amplitude and frequency of the incident wave
Bthe amplitude of the incident wave and the width of the gap
Cthe wavelength and amplitude of the incident wave
Dthe wavelength of the incident wave and the width of the gap
Mark scheme
33Oct / Nov 2020 · Paper 11 · Q27Show mark scheme →
Asound waves
Bultraviolet waves
Cvisible light waves
DX-rays
Mark scheme
34Oct / Nov 2020 · Paper 12 · Q28Show mark scheme →
AThe radio waves are coherent but the microwaves are not.
BThe radio waves are diffracted around the mountain but the microwaves are not.
CThe radio waves are reflected by the mountain but the microwaves are not.
DThe radio waves travel at the speed of light but the microwaves do not.
Mark scheme
35Oct / Nov 2020 · Paper 13 · Q28Show mark scheme →
Athe change in observed frequency when a wave source moves relative to an observer
Bthe formation of nodes and antinodes by two progressive waves travelling in opposite directions
Cthe spreading of a wave around the edge of an obstacle
Dthe superposition of two waves when they meet
Mark scheme
36May / June 2020 · Paper 11 · Q28Show mark scheme →
AThe wave is able to travel in a vacuum.
BThe wave is progressive.
CThe wave has a large amplitude.
DThe wave has a long wavelength.
Mark scheme
37May / June 2020 · Paper 12 · Q28Show mark scheme →
Acoherence
Bdiffraction
Cinterference
Dreflection
Mark scheme
38May / June 2020 · Paper 13 · Q28Show mark scheme →
ADiagram A
BDiagram B
CDiagram C
DDiagram D
Mark scheme
39Feb / March 2020 · Paper 12 · Q27Show mark scheme →
Acoherence
Bdiffraction
Cinterference
Dsuperposition
Mark scheme
40Oct / Nov 2019 · Paper 11 · Q27Show mark scheme →
Aθ decreases, wavelength remains the same
Bθ increases, wavelength remains the same
Cθ remains the same, wavelength decreases
Dθ remains the same, wavelength increases
Mark scheme
41May / June 2019 · Paper 11 · Q28Show mark scheme →
ADiagram A
BDiagram B
CDiagram C
DDiagram D
Mark scheme
42May / June 2019 · Paper 13 · Q27Show mark scheme →
AIncrease the amplitude of the waves.
BIncrease the frequency of the waves.
CIncrease the wavelength of the waves.
DIncrease the width of the gap.
Mark scheme
43Oct / Nov 2018 · Paper 11 · Q27Show mark scheme →
Alaser light travelling along an optic fibre
Blight waves forming images on a cinema screen
Cmicrowaves passing the edge of a metal plate
Dsound waves diverging as they pass through air
Mark scheme
44Oct / Nov 2018 · Paper 12 · Q28Show mark scheme →
AThere is diffraction and the wavelength decreases.
BThere is diffraction and the wavelength stays the same.
CThere is no diffraction and the wavelength decreases.
DThere is no diffraction and the wavelength stays the same.
Mark scheme
45Oct / Nov 2018 · Paper 13 · Q27Show mark scheme →
AA wave bounces back from a surface.
BA wave passes from one medium into another.
CA wave passes through an aperture.
DWaves from two identical sources are superposed.
Mark scheme
46May / June 2018 · Paper 13 · Q25Show mark scheme →
Athe amplitude and frequency of the incident wave
Bthe amplitude of the incident wave and the width of the gap
Cthe wavelength and amplitude of the incident wave
Dthe wavelength of the incident wave and the width of the gap
Mark scheme
47Feb / March 2018 · Paper 12 · Q29Show mark scheme →
AA source of waves moves towards a stationary observer.
BA wave is partially blocked by an obstacle.
CTwo coherent waves are superposed.
DTwo waves of equal speed and frequency are travelling through the same part of a medium in opposite directions.
Mark scheme
48Oct / Nov 2017 · Paper 11 · Q24Show mark scheme →
Amicrowaves passing a steel post
Bradio waves passing a copper wire
Csound waves passing a human hair
Dvisible light waves passing a gate post
Mark scheme
49Oct / Nov 2017 · Paper 11 · Q29Show mark scheme →
Avibration frequency f/2, gap width x/2
Bvibration frequency f/2, gap width 2x
Cvibration frequency 2f, gap width x/2
Dvibration frequency 2f, gap width 2x
Mark scheme
50Oct / Nov 2017 · Paper 12 · Q28Show mark scheme →
ADiagram A
BDiagram B
CDiagram C
DDiagram D
Mark scheme
51Oct / Nov 2017 · Paper 12 · Q29Show mark scheme →
AThe wavelength of light is longer than the wavelength of radio waves so there is more diffraction of light over the hill.
BThe wavelength of light is shorter than the wavelength of radio waves so there is more diffraction of light over the hill.
CThe wavelength of radio waves is longer than the wavelength of light so there is more diffraction of radio waves over the hill.
DThe wavelength of radio waves is shorter than the wavelength of light so there is more diffraction of radio waves over the hill.
Mark scheme
52Oct / Nov 2017 · Paper 13 · Q29Show mark scheme →
Aa small dot
Ba horizontal line
Ca vertical line
Da large circle
Mark scheme
53Feb / March 2017 · Paper 12 · Q28Show mark scheme →
A\frac{3\lambda}{2c}
B\frac{2\lambda}{c}
C\frac{3\lambda}{c}
D\frac{4\lambda}{c}
Mark scheme
54Oct / Nov 2016 · Paper 11 · Q27Show mark scheme →
ADiagrams X and Y both illustrate diffraction.
BDiagrams X and Y both illustrate interference.
COnly diagram X illustrates interference.
DOnly diagram Y illustrates diffraction.
Mark scheme
55Oct / Nov 2016 · Paper 13 · Q27Show mark scheme →
ADiagrams X and Y both illustrate diffraction.
BDiagrams X and Y both illustrate interference.
COnly diagram X illustrates interference.
DOnly diagram Y illustrates diffraction.
Mark scheme
56May / June 2016 · Paper 11 · Q25Show mark scheme →
Aincreasing the frequency of the waves
Bincreasing the width of the gap
Creducing the wavelength of the waves
Dreducing the width of the gap
Mark scheme
57May / June 2016 · Paper 12 · Q26Show mark scheme →
Athe addition of the amplitudes of two beams of light which are in phase
Bthe change in direction of a beam of light when passing from air into water
Cthe separation of a beam of white light into a spectrum of colours using a prism
Dthe spreading of a beam of light as it passes through a small hole
Mark scheme
58May / June 2016 · Paper 13 · Q26Show mark scheme →
Acoherence
Bdiffraction
Cinterference
Dreflection
Mark scheme
59Feb / March 2016 · Paper 12 · Q23Show mark scheme →
Athe ability to hear around corners
Bthe ability to hear high frequency and low frequency sound waves
Cthe ability to hear loud and quiet sounds
Dthe ability to hear sound through a brick wall
Mark scheme