Numbers
AQA A-Level Physics 7408
Measurements and Their Errors
Particles and Radiation
Topic overviewConstituents of the atomStable and unstable nucleiParticles, antiparticles and photonsParticle interactionsClassification of particlesQuarks and antiquarksApplications of conservation lawsThe photoelectric effectCollisions of electrons with atomsEnergy levels and photon emissionWave-particle duality
Waves
Mechanics and Materials
Electricity
Further Mechanics and Thermal Physics
Fields and Their Consequences
Topic overviewFieldsNewton's lawGravitational field strengthGravitational potentialOrbits of planets and satellitesCoulomb's lawElectric field strengthElectric potentialCapacitanceParallel plate capacitorEnergy stored by a capacitorCapacitor charge and dischargeMagnetic flux densityMoving charges in a magnetic fieldMagnetic flux and flux linkageElectromagnetic inductionAlternating currentsTransformers
Nuclear Physics
AstrophysicsOptional topic
Topic overviewAstronomical telescope consisting of two converging lensesReflecting telescopesSingle dish radio telescopes, I-R, U-V and X-ray telescopesAdvantages of large diameter telescopesClassification by luminosityAbsolute magnitude, MClassification by temperature, black-body radiationPrinciples of the use of stellar spectral classesThe Hertzsprung-Russell (HR) diagramSupernovae, neutron stars and black holesDoppler effectHubble's lawQuasarsDetection of exoplanets
Medical PhysicsOptional topic
Topic overviewPhysics of visionDefects of vision and their correction using lensesEar as a sound detection systemSensitivity and frequency responseDefects of hearingSimple ECG machines and the normal ECG waveformUltrasound imagingFibre optics and endoscopyMagnetic resonance (MR) scannerThe physics of diagnostic X-raysImage detection and enhancementAbsorption of X-raysCT scannerImaging techniquesHalf-lifeGamma cameraUse of high-energy X-raysUse of radioactive implantsImaging comparisons
Engineering PhysicsOptional topic
Turning Points in PhysicsOptional topic
Topic overviewCathode raysThermionic emission of electronsSpecific charge of the electronPrinciple of Millikan's determination of the electronic charge, eNewton's corpuscular theory of lightSignificance of Young's double slits experimentElectromagnetic wavesThe discovery of photoelectricityWave–particle dualityElectron microscopesThe Michelson-Morley experimentEinstein's theory of special relativityTime dilationLength contractionRelativistic mass and energy
ElectronicsOptional topic
Topic overviewMOSFET (metal-oxide semiconducting field-effect transistor)Zener diodePhotodiodeHall effect sensorDifference between analogue and digital signalsLC resonance filtersThe ideal operational amplifierInverting amplifier configurationNon-inverting amplifier configurationSumming amplifier configurationReal operational amplifiersCombinational logicSequential logicAstablesPrinciples of communication systemsTransmission mediaTime-division multiplexingAmplitude (AM) and frequency modulation (FM) techniques
Waves
- 6 subtopics
- 31 things to know
- Papers 1 and 3
What Waves covers
Waves is examined on Papers 1 and 3. It covers the properties every wave shares, the stationary waves formed by superposition, and the interference, diffraction and refraction that follow from treating light as a wave.
Where it is assessed
Papers 1 and 3
Core content, then practical skills and data analysis.
Check the AQA specification ↗The 6 subtopics
Each one has its own page.
- Progressive wavesAmplitude, frequency, wavelength, speed, phase and phase difference, and the wave equation.Open →
- Longitudinal and transverse wavesThe difference between the two, and why only transverse waves can be polarised.Open →
- Principle of superposition of waves and formation of stationary wavesNodes and antinodes, the harmonics of a string, and the first harmonic formula.Open →
- InterferenceCoherence and path difference, Young's double slit experiment, fringe spacing, and laser safety.Open →
- DiffractionSingle slit diffraction, the grating equation and its derivation, and the orders of maxima.Open →
- Refraction at a plane surfaceRefractive index and Snell's law, total internal reflection, and optical fibres and dispersion.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
What are wave speed, wavelength and phase?
Key term
What is phase difference, and in what units can it be given?
Numbers
What equation links wave speed, frequency and the distance between successive peaks?
Numbers
Explain the physical meaning of the relationship f = 1/T
Numbers
How is frequency found from the time for one cycle, and how are phase units converted?
Key term
Which waves are transverse, and how do they oscillate relative to energy transfer?
Key term
Why can only transverse waves be polarised?
Process
What happens to signal reception if a receiving aerial is not aligned with the plane of polarisation of the transmitted wave?
Numbers
What is the phase relationship along a stationary wave, and how far apart are a node and antinode?
Numbers
What is the formula for the first harmonic on a string, what does f represent, and what is the formula used for?
Numbers
How do wavelength and the nodes and antinodes differ between the first and second harmonics?
Numbers
How does the nth harmonic relate to the first, and what forms when two waves meet head on?
Process
How do tension and length change the note a string produces, and how does amplitude vary along it?
Process
How does a greater mass per unit length change the note a string produces?
Numbers
What is the fringe spacing formula, and where do bright fringes fall?
Numbers
What do λ, D and s stand for, and how does wavelength change the pattern?
Key term
What safety precautions apply when using a laser?
Process
Why does white light produce coloured fringes, and which colour lies furthest out?
Numbers
Why is the central fringe white in white light, and what does wider slit separation do?
Key term
How can interference of sound waves be demonstrated in a laboratory?
Key term
According to quantum theory, what dual nature does light exhibit?
Numbers
What is the diffraction grating equation, and what does d stand for?
Numbers
What does θ represent, and what is the path difference between rays from neighbouring slits?
Numbers
Why do bright maxima appear at particular angles in a diffraction grating?
Key term
What is the purpose of a diffraction grating in a spectrometer?
Numbers
How is refractive index defined, and what can Snell's law be used to find?
Process
How does the cladding compare with the core, and how does a fibre carry light?
Key term
What is a step index fibre, why is cladding needed, and why does material dispersion occur?
Process
How does pulse broadening affect data transmission in optical fibres?
Key term
Why are repeaters or amplifiers needed along long optical fibre links?
Take Waves further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Progressive wave vs Stationary wave
Progressive wave: disturbance transferring energy through space. Stationary wave: fixed pattern formed by superposed opposite waves.
Refraction vs Diffraction
Refraction: direction change caused by wave-speed change. Diffraction: spreading when waves pass an aperture or edge.
Coherent sources vs Incoherent sources
Coherent sources: sources maintaining constant phase difference. Incoherent sources: sources with changing phase difference.
Questions from this topic
Each one with the model answer underneath.
- 1
How does a progressive wave transfer energy without transferring matter?
Model answer
Energy is transferred from one place to another as particles of the medium oscillate about fixed equilibrium positions, passing energy to neighbouring particles without themselves moving along with the wave.
- 2
What happens to the particles of a medium when a progressive wave passes through it?
Model answer
The particles oscillate about their fixed equilibrium positions; they do not travel with the wave.
- 3
Define amplitude in the context of wave motion.
Model answer
Amplitude is the maximum displacement of a particle from its equilibrium position.
- 4
What is meant by the frequency of a wave?
Model answer
Frequency is the number of complete oscillations passing a point per unit time.
- 5
State the SI unit of frequency.
Model answer
Hertz (Hz).
- 6
Define wavelength.
Model answer
Wavelength is the minimum distance between two points oscillating in phase, such as successive crests or troughs.
What is inside Levo
Six ways to work the same material.
Waves revision questions
- What does Waves cover in AQA A-Level Physics?
- 6 subtopics: progressive waves, longitudinal and transverse waves, principle of superposition of waves and formation of stationary waves, interference, diffraction and refraction at a plane surface. Each one has its own page with questions and model answers.
- How is Waves organised?
- By the AQA 7408 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Waves, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
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