Superposition — AS & A Level Physics (9702) questions by topic
Superposition topics range across polarising filters and amplitude, stationary waves on a stretched string, double-slit interference fringe spacing, and the conditions two waves need to interfere, carrying from 1 to 9 marks in this A Level Physics set.
Calculate, identify and deduce feature heavily among the command words, with explain and state also common: explain why fringe spacing changes, or state the resultant displacement rule precisely. 77 real questions from 2023 to 2025 papers make up this page. Submit each answer for instant marking to catch a millimetre-to-metre conversion missed on slit separation, or a maximum wrongly marked on an interference diagram.
What examiners look for
- Examiners repeatedly find candidates fail to state that resultant displacement equals the sum of individual displacements, sometimes confusing displacement with amplitude.
- A common mistake is not converting slit separation and fringe width from millimetres to metres before substituting values.
- Reports note many candidates confuse the width of a single slit with the separation between slits, wrongly predicting increased fringe separation.
- A recurring criticism is not following instructions precisely when labelling a cross on a diagram, or marking a wrong maximum entirely.
- Only the strongest candidates explain that narrower slits cause more diffraction and therefore more fringes, without any change in fringe spacing.
May–June 2025, Paper 11
One wave has an amplitude of 2A. A second wave has an amplitude of A/2. The waves are otherwise identical. The two waves travel in opposite directions and overlap. What is the…
Answer this question and get it marked →Light of wavelength 680 nm is incident normally on a diffraction grating with 450 lines mm^-1. What is the angle of diffraction of the second-order maximum in the diffraction…
Answer this question and get it marked →A hollow tube is closed at one end and open at the other. A stationary sound wave of the lowest possible frequency, 820 Hz, is produced in the tube. The speed of sound in air is…
Answer this question and get it marked →May–June 2025, Paper 12
A teacher removes the turntable from a microwave oven and places a bar of chocolate in the oven. She then switches the oven on for a short time. A stationary wave is formed in the…
Answer this question and get it marked →A student uses a diffraction grating to determine the wavelength of visible light from a source. The diffraction grating has 300 lines per mm. The student measures the angle θ of…
Answer this question and get it marked →Two waves meet. What is not a necessary condition for the waves to produce a stationary wave? A They must be of the same type. B They must have the same period. C They must have…
Answer this question and get it marked →Light of a single wavelength is incident normally on a double slit. Interference fringes are observed on a screen. The distance from the double slit to the screen is 0.60 m and…
Answer this question and get it marked →May–June 2025, Paper 13
Two coherent sources X and Y emit waves in phase. A point Z is such that XZ = 70 cm and YZ = 110 cm. The phase difference between the waves at Z is 180°. What is a possible…
Answer this question and get it marked →Which statement correctly describes the principle of superposition? A When two or more waves meet at a point, the resultant displacement is the vector sum of the individual…
Answer this question and get it marked →Plane waves in a ripple tank pass through a gap in a barrier. The gap is then made smaller. Which diagram shows the new diffraction pattern? A, B, C and D show different wavefront…
Answer this question and get it marked →In a double slit interference experiment, which change would increase the fringe separation? A increasing the distance from the slits to the screen B increasing the slit…
Answer this question and get it marked →May–June 2025, Paper 14
A pipe of length 100 cm is open at both ends. A loudspeaker situated at one end of the pipe can emit sound of different wavelengths. Which wavelength can produce a stationary wave…
Answer this question and get it marked →A student makes a sound at point R near a building. A second student, standing at point S around the corner of the building, hears the sound. The building is a solid structure and…
Answer this question and get it marked →Red light of a single wavelength from a laser is incident on a double slit. A pattern of interference fringes is observed on a flat screen that is placed parallel to the double…
Answer this question and get it marked →An electromagnetic wave is incident normally on a diffraction grating. A second-order maximum is produced at an angle of 30° to the direction of the incident light. The grating…
Answer this question and get it marked →May–June 2025, Paper 21
State the principle of superposition.
Answer this question and get it marked →May–June 2025, Paper 23
May–June 2024, Paper 11
A plane polarised wave has amplitude A. The wave is incident normally on a polarising filter. The transmission axis of the filter is at angle θ to the plane of polarisation of the…
Answer this question and get it marked →Light of frequency 6.7 × 10¹⁴ Hz in a vacuum is incident normally on a diffraction grating that contains 4.0 × 10⁵ lines m⁻¹. What is the angle between the adjacent second and…
Answer this question and get it marked →Microwaves are emitted from two sources at points X and Y. The two waves meet at point Z. The diagram shows the paths of the two waves from X and Y converging at Z. The waves…
Answer this question and get it marked →May–June 2024, Paper 12
A diffraction grating with N lines per metre is used to diffract light of various wavelengths λ. The graph shows the relation between the diffraction angle θ and λ for different…
Answer this question and get it marked →A stationary sound wave is formed in the air column inside a tube that is open at both ends. The stationary wave has three nodes. How many antinodes does it have? A 1 B 2 C 3 D 4
Answer this question and get it marked →Interference fringes of separation x are observed on a screen at a distance of 1.00 m from a double slit that is illuminated by yellow light of wavelength 600 nm. At which…
Answer this question and get it marked →May–June 2024, Paper 13
Two waves superpose. A resultant wave pattern is formed. Which statement about the two waves must be correct? A They have the same amplitude. B They are of the same type. C They…
Answer this question and get it marked →A water wave passes through a gap in a harbour wall and diffracts. The gap has a width of 8 m. The wave travels directly towards the gap. For which wavelength is the diffraction…
Answer this question and get it marked →Light of wavelength 5.50 × 10⁻⁷ m from a laser is incident normally on a diffraction grating. The diffracted light is incident on a semicircular screen. A total of 9 bright dots…
Answer this question and get it marked →May–June 2024, Paper 21
A stretched string PQ has length 1.2 m. One end of the string is attached to a vibration generator and the other end is attached to a wall, as shown in Fig. 5.1. The vibration…
Answer this question and get it marked →May–June 2024, Paper 22
Light of a single frequency is incident normally on a diffraction grating. An interference pattern of bright and dark fringes forms on the semicircular screen shown in Fig. 6.1.…
Answer this question and get it marked →October–November 2024, Paper 11
Three statements about two progressive waves are listed. 1 The waves have the same frequency. 2 The waves have the same amplitude. 3 The waves are emitted with a constant phase…
Answer this question and get it marked →Waves P and Q have the same amplitude. The waves meet in phase at point X and interfere to give a resultant wave with intensity I. The amplitude of wave P is doubled. What is the…
Answer this question and get it marked →Light of wavelength lambda is incident normally on a diffraction grating with a total number of N lines in width w. A second order maximum is observed at an angle of diffraction…
Answer this question and get it marked →October–November 2024, Paper 12
What happens when two waves superpose at a point? A Their amplitudes are added together. B Their displacements are added together. C Their frequencies are added together. D Their…
Answer this question and get it marked →An electromagnetic wave is diffracted as it passes through a single slit. The width of the slit is larger than the wavelength of the wave. Which change will decrease the amount of…
Answer this question and get it marked →The diagram shows visible light incident normally on a diffraction grating. A pattern of intensity maxima forms on the screen. A line connecting the centre of the fourth order…
Answer this question and get it marked →A horizontal glass tube, closed at one end, has a layer of dust laid inside it on its lower side. Sound is emitted from a loudspeaker that is placed near the open end of the tube.…
Answer this question and get it marked →October–November 2024, Paper 13
A stationary wave is set up in a stretched string. Which distance is equal to the wavelength of the wave? A double the distance between adjacent antinodes B half the distance…
Answer this question and get it marked →A source of coherent light is incident on two slits, P and Q, which are placed 80 mm apart. The light has a single frequency of 1.5 x 10^12 Hz. The light from the slits meets on a…
Answer this question and get it marked →A vibrating bar produces surface water waves in a ripple tank. The wavelength of the waves is 5.0 cm and they pass through a gap of width 20 cm. Which change will increase the…
Answer this question and get it marked →October–November 2024, Paper 21
Two coherent sources X and Y of microwaves of frequency 2.5 x 10^10 Hz are a distance of 0.18 m apart in a vacuum, as shown in Fig. 6.1. There is a phase difference of 90 degrees…
Answer this question and get it marked →October–November 2024, Paper 23
A stationary wave is formed on a string XY that has a length of 0.48 m. Fig. 5.1 shows the string at one instant in time. The string has fixed ends at X and Y, with the wave…
Answer this question and get it marked →February–March 2023, Paper 12
A musical instrument is made using a long tube with a mouthpiece at one end. The other end is open and flared. A musician maintains stationary sound waves with a node at the…
Answer this question and get it marked →Two waves of equal frequency and amplitude are travelling in opposite directions along a stretched string. When they meet, they form a stationary wave with three nodes and two…
Answer this question and get it marked →A transmitting mast sends out microwaves of wavelength 1.5 cm and radio waves of wavelength 1.5 km. A receiving aerial behind a mountain can detect the radio waves but not the…
Answer this question and get it marked →Waves are emitted from two coherent sources. Which statement about the waves must be correct? A They are in phase. B They are transverse waves. C They have a constant phase…
Answer this question and get it marked →The diagram shows a screen that is a distance L from a diffraction grating. The grating has a total number of N lines. Any two adjacent lines are a distance d apart. A beam of…
Answer this question and get it marked →May–June 2023, Paper 11
Two progressive waves meet at a point. Which condition must be met for superposition of the waves to occur? A The waves must be coherent. B The waves must be of the same type. C…
Answer this question and get it marked →A string is stretched between a vibration generator and a fixed point. When the vibration generator is vibrating at a frequency f, a stationary wave with five nodes is created on…
Answer this question and get it marked →A ripple tank and a barrier with a single gap are used to demonstrate the diffraction of surface ripples on water. Initially, the wavelength of the ripples is five times smaller…
Answer this question and get it marked →A laser produces a beam of light of wavelength 650 nm. The beam is incident normally on two slits that are a distance of 0.12 mm apart. A screen is placed parallel to the slits.…
Answer this question and get it marked →A beam of light from a laser is incident normally on a diffraction grating. The diagram shows only the second-order maxima that are produced. The grating has a line spacing of 1.0…
Answer this question and get it marked →May–June 2023, Paper 12
A stationary wave is formed by two progressive waves travelling in opposite directions along the same line of travel. Which statement about the two progressive waves is not…
Answer this question and get it marked →The sound from a loudspeaker placed above a tube causes resonance of the air in the tube. A stationary wave is formed with two nodes and two antinodes, as shown. The tube has…
Answer this question and get it marked →A continuous progressive water wave in a ripple tank passes through a gap in a barrier and diffracts. The width of the gap is greater than the wavelength of the wave. Which change…
Answer this question and get it marked →The diagram shows a view from above of a double-slit interference demonstration. L is a monochromatic light source with a vertical filament, B is a barrier with two narrow…
Answer this question and get it marked →Green light of wavelength 550 nm is incident normally on a diffraction grating and produces a diffraction pattern on a screen placed 3.5 m from the diffraction grating. The…
Answer this question and get it marked →May–June 2023, Paper 13
The diagram shows a string stretched between fixed points X and Y with a stationary wave on the string. The solid curve shows the string at maximum displacement at time t0; the…
Answer this question and get it marked →The variation with distance x of the intensity I along a stationary sound wave in air is shown. The intensity is zero at x = 5.0 cm and maximum at x = 0 and x = 10.0 cm. The speed…
Answer this question and get it marked →An experiment is set up to demonstrate the diffraction of water waves in a ripple tank. The waves pass through a gap of width w and some diffraction of the waves is observed. The…
Answer this question and get it marked →Two coherent electromagnetic waves are travelling in a vacuum. The two waves meet at a point. At this point, the two waves have different intensities. Which statement about the…
Answer this question and get it marked →A parallel beam of light of wavelength 600 nm is incident normally on a diffraction grating. The distance between adjacent slits in the grating is 2.0 x 10^-6 m. A screen is…
Answer this question and get it marked →October–November 2023, Paper 11
In an experiment, a stationary wave is formed on a string stretched horizontally between two fixed points. Which statement about the experiment is correct? A At certain times, the…
Answer this question and get it marked →A musical organ produces notes by blowing air into a set of pipes that are open at one end and closed at the other. The speed of sound in the air in the pipes is 320 m s^-1. What…
Answer this question and get it marked →In an experiment, water waves in a ripple tank are incident on a gap. Some diffraction of the water waves is observed. Which change to the experiment would provide a better…
Answer this question and get it marked →Light of wavelength lambda is emitted from two point sources R and S and falls onto a distant screen. At point P on the screen, the light intensity is zero. What could explain the…
Answer this question and get it marked →A beam of red light of wavelength 720 nm is incident normally on a diffraction grating and produces a diffraction pattern on a screen placed parallel to the grating. The beam of…
Answer this question and get it marked →October–November 2023, Paper 12
What can explain how stationary waves are formed from progressive waves? A diffraction B polarisation C superposition D the Doppler effect
Answer this question and get it marked →A pipe has a length of 2.0 m. It is open at one end and closed at the other end. A stationary sound wave is set up within the pipe. There are four nodes (N) and four antinodes (A)…
Answer this question and get it marked →A teacher is explaining diffraction to a group of students. Which piece of apparatus is most appropriate for the teacher to use to demonstrate diffraction? A a long spring B a…
Answer this question and get it marked →Coherent light of constant wavelength is incident normally on a double slit. Interference fringes are formed on a screen that is a fixed distance from the double slit. The screen…
Answer this question and get it marked →Light of wavelength 690 nm passes through a diffraction grating with 300 lines per mm, producing a series of bright spots (maxima) on a screen. What is the total number of bright…
Answer this question and get it marked →October–November 2023, Paper 13
Which statement concerning a stationary wave is correct? A All the particles between two adjacent nodes oscillate in phase. B The amplitude of the stationary wave is equal to the…
Answer this question and get it marked →Stationary sound waves can be formed in the air columns of pipes. One type of pipe is closed at one end and open at the other end. Another type of pipe is open at both ends. Which…
Answer this question and get it marked →Water waves in a ripple tank are made to pass through a small gap. Which diagram shows the waves after they have passed through the gap? Four candidate diagrams A, B, C and D show…
Answer this question and get it marked →Light of a single wavelength is incident normally on a double slit. The slit separation can be varied. A screen is placed a fixed distance away from the double slit. The screen…
Answer this question and get it marked →A diffraction grating is used to measure the wavelength of light. The spacing of the slits in the grating is 1.15 x 10^-6 m. The angle between the first-order diffraction maxima…
Answer this question and get it marked →October–November 2023, Paper 21
October–November 2023, Paper 23
Two point sources, A and B, produce coherent electromagnetic waves. The waves from A and B are emitted in phase and have wavelength lambda, as shown in Fig. 5.1 (not to scale).…
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