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Section 1: Measurements and Their Errors
3.1.1 - Use of SI Units and Their PrefixesPhysics is a quantitative science built on precise measurement. Every measurement requires a number and a unit, and scientists worldwide use the same system of units -- the Systeme International (SI) -- to ensure consistency and clarity. This lesson covers the six SI base units required by the AQ...
3.1.2 - Limitation of Physical MeasurementsEvery measurement in physics carries some degree of doubt. Understanding the nature, magnitude, and propagation of that doubt is essential: it determines how many significant figures you can justify, whether your result agrees with a theoretical prediction, and how you should design an experiment...
3.1.3 - Estimation of Physical QuantitiesPhysicists routinely need to judge whether a calculated answer is reasonable, compare the scales of different phenomena, or make quick predictions without precise data. This lesson develops your ability to work with orders of magnitude and to produce sensible estimates of physical quantities and...
Section 2: Particles and Radiation / 2.1 - Particles
3.2.1.1 - Constituents of the AtomEvery element is built from just three subatomic particles: protons, neutrons, and electrons. In this lesson you will learn the properties of these particles, how to describe nuclei using standard notation, what isotopes are, how isotopic data is used, and how to calculate the specific charge of...
3.2.1.2 - Stable and Unstable NucleiEvery atomic nucleus contains protons packed tightly together, and since like charges repel, there must be something powerful enough to overcome this electrostatic repulsion and hold the nucleus together. In this lesson you will learn about the strong nuclear force, understand why some nuclei are...
3.2.1.3 - Particles, Antiparticles and PhotonsElectromagnetic radiation can be described as photons, and the same energy ideas explain how matter and antimatter can be destroyed or created. In this lesson you will use the photon model, compare particles with their antiparticles, and link annihilation and pair production through conservation...
3.2.1.4 - Particle InteractionsWhen particles attract, repel, or change identity, physicists describe the process as an interaction. This lesson focuses on the four fundamental interactions, the idea of exchange particles, and the simple electromagnetic and weak-interaction diagrams you need to recognise for A-Level Physics.
3.2.1.5 - Classification of ParticlesThe subatomic world contains a rich zoo of particles discovered through cosmic ray experiments and high-energy accelerator collisions. To make sense of this diversity, physicists classify particles into groups based on the fundamental interactions they experience. In this lesson you will learn th...
3.2.1.6 - Quarks and AntiquarksThe hadrons in this part of the course are not fundamental particles. They are made from quarks and antiquarks, and their charge, baryon number, and strangeness can be found by adding the properties of those constituent particles. In this lesson you will use only the quarks named in the specifica...
3.2.1.7 - Applications of Conservation LawsParticle interactions are not judged by guesswork. You decide whether a reaction is possible by checking a short list of conservation laws and, for beta decay, by tracking the quark change that makes the reaction weak. In this lesson you will practise that method so you can decide quickly whether...
Section 2: Particles and Radiation / 2.2 - Electromagnetic Radiation and Quantum Phenomena
3.2.2.1 - The Photoelectric EffectThe photoelectric effect showed that light does not behave like a continuous wave in every situation. Electrons are emitted from a metal only when the light has a high enough frequency, and that simple fact led Einstein to the photon model of light. In this lesson you will focus on the observatio...
3.2.2.2 - Collisions of Electrons with AtomsWhen a fast-moving electron collides with an atom, it can transfer energy to that atom. If the transfer is large enough, the atom can be ionised or excited. These ideas are used to explain fluorescent tubes and are usually measured in electron volts rather than joules because the energies are so...
3.2.2.3 - Energy Levels and Photon EmissionWhen light from atomic hydrogen is viewed through a diffraction grating, it does not spread into every possible colour. Instead, a few sharp lines appear at specific wavelengths. That observation is strong evidence that atoms can only gain or lose particular amounts of energy. In this lesson, you...
3.2.2.4 - Wave-Particle DualityEverything you have studied so far in quantum physics points to a strange conclusion: the universe does not draw a clean line between waves and particles. Light, which you have seen diffract and interfere like a wave, can also knock electrons out of metals like a stream of particles. Electrons, w...
Section 3: Waves / 3.1 - Progressive and Stationary Waves
3.3.1.1 - Progressive WavesProgressive waves are described using a small set of linked quantities: amplitude, wavelength, frequency, period, speed, phase, and phase difference. In this lesson, we will build those ideas carefully so that the equations and definitions fit together rather than feeling like isolated facts.
3.3.1.2 - Longitudinal and Transverse WavesWaves can be classified by how the oscillations are arranged relative to the direction of energy transfer. That single idea explains the difference between sound waves, electromagnetic waves, and waves on a string, and it also explains why polarisation is such strong evidence for the nature of tr...
3.3.1.3 - Principle of Superposition of Waves and Formation of Stationary WavesWhen two waves overlap, they do not stop being waves. They pass through each other, and at every point the displacements combine. That simple rule explains the formation of stationary waves on strings, with microwaves, and with sound, and it leads directly to the harmonic patterns and frequency e...
RP01 - Stationary Waves on a StringEvery stringed instrument you have ever heard works because of the physics in this practical. When you pluck a guitar string, progressive waves travel in both directions, reflect off the fixed ends, and superpose to form a stationary wave. The pitch of the note — its frequency — depends on three...
Section 3: Waves / 3.2 - Refraction, Diffraction and Interference
3.3.2.1 - InterferenceInterference shows what happens when waves overlap. In light, it produces the bright and dark fringes of Young's double-slit experiment; in sound and other electromagnetic waves, it produces alternating maxima and minima of intensity. In this lesson you will learn the conditions for interference,...
RP02 - Interference EffectsRP02 turns the interference ideas from Topic 3.3.2.1 into measurements. You will set up Young's double slit and a diffraction grating, collect data that can be graphed, and use those graphs to determine the wavelength of laser light. The theory still matters, but this lesson is mainly about the p...
3.3.2.2 - DiffractionWhen light meets a narrow slit or a regularly spaced set of slits, it does not simply continue as one straight beam. It spreads, interferes with itself, and produces patterns that reveal wavelength and structure. In this lesson you will focus on the appearance of single-slit diffraction patterns,...
3.3.2.3 - Refraction at a Plane SurfaceWhen light crosses a boundary between two transparent substances, its speed changes. That change of speed changes the direction of travel unless the ray arrives along the normal. In this lesson you will connect ray diagrams to refractive index, Snell's law, total internal reflection, and the way...
Section 4: Mechanics and Materials / 4.1 - Force, Energy and Momentum
3.4.1.1 - Scalars and VectorsUnderstanding the difference between scalar and vector quantities is fundamental to physics. Many physical quantities — such as force, velocity, and displacement — require both a magnitude and a direction to be fully described. In this lesson, you will learn to distinguish scalars from vectors, a...
3.4.1.2 - MomentsForces can do more than speed objects up or slow them down. If a force acts away from a turning point, it can also make an object rotate. In this lesson, you will focus on the turning effect of forces, how balanced turning effects lead to equilibrium, how the centre of mass helps you place an obj...
3.4.1.3 - Motion Along a Straight LineHow do we describe the motion of objects precisely? Whether it is a car braking on a motorway, a ball dropped from a bridge, or a rocket launching from a pad, the same set of definitions and equations lets us predict exactly where an object will be and how fast it will be moving at any instant. I...
RP03 - Determination of g by Free FallEvery object near the Earth's surface accelerates downward at roughly the same rate, regardless of its mass, provided air resistance is negligible. This Required Practical asks you to measure that acceleration, $g$, using a falling ball bearing, a ruler, and precision timing. The key challenge is...
3.4.1.4 - Projectile MotionA projectile problem becomes manageable once you split one curved path into two simpler motions. In the ideal model, gravity changes only the vertical motion while the horizontal motion continues independently. After that, we can add the real-world complications the specification wants qualitativ...
3.4.1.5 - Newton's Laws of MotionNewton's laws give us a clean way to connect forces to motion. In this lesson, you will see how the first law describes equilibrium, how the second law turns a resultant force into a calculation, how the third law explains interaction pairs, and how free-body diagrams help you decide which forces...
3.4.1.6 - MomentumMomentum links mass, velocity, force, and collisions in one framework. In this lesson, you will calculate momentum, use Newton's second law in momentum form, find impulse from force-time information, apply conservation of momentum in one dimension, and connect impact physics to safer and more eth...
3.4.1.7 - Work, Energy and PowerWhen a force makes something move, energy is transferred. This lesson stays focused on the core calculations you need here: work done by a force, power as the rate of doing work, the meaning of the area under a force-displacement graph, and efficiency.
3.4.1.8 - Conservation of EnergyEnergy is one of the most fundamental concepts in physics. Every process in the universe — from a pendulum swinging to a roller coaster descending a track — obeys a single, unbreakable rule: energy is always conserved. In this lesson, you will learn how to apply the principle of conservation of e...
Section 4: Mechanics and Materials / 4.2 - Materials
3.4.2.1 - Bulk Properties of SolidsMaterials respond to forces in very different ways: a steel cable barely stretches under enormous loads, whereas a rubber band deforms readily in your hands. Understanding the mechanical behaviour of solids --- from density through to fracture --- is essential in physics and engineering. This les...
3.4.2.2 - The Young ModulusWhen we compare the stiffness of different materials, we need a property that does not depend on the dimensions of the sample. A thick steel cable and a thin steel wire are made of the same material, yet the cable is much harder to stretch. The Young modulus strips away the influence of length an...
RP04 - Determination of the Young ModulusThe Young modulus is the single number that tells you how stiff a material is --- how much it resists being stretched or compressed. In this required practical you will load a thin wire with known masses, measure tiny extensions to the nearest tenth of a millimetre, and extract the Young modulus...
Section 5: Electricity / 5.1 - Current Electricity
3.5.1.1 - Basics of ElectricityElectric current, potential difference, and resistance are the three foundation quantities for circuit physics. In this lesson, you will meet each quantity as a precise definition, learn the equation linked to it, and see how the three ideas connect when you solve simple circuit problems.
3.5.1.2 - Current-Voltage CharacteristicsCurrent-voltage characteristics show how a component responds when the potential difference across it changes. By reading the shape of an I-V graph, you can tell whether a component has constant resistance, whether its resistance changes with temperature, or whether it allows current to flow much...
3.5.1.3 - ResistivityEvery conducting material resists the flow of charge to some degree, but how do we compare the resistance of different materials fairly, independent of their size and shape? The answer lies in a property called resistivity. In this lesson, you will learn how resistivity relates resistance to the...
RP05 - Determination of Wire ResistivityEvery conducting material has a fingerprint property called resistivity that tells you how strongly it opposes current, independent of the wire's shape or size. In this Required Practical you will measure the resistivity of constantan wire by systematically varying its length, recording resistanc...
3.5.1.4 - CircuitsUnderstanding how components combine in series and parallel is the foundation of all circuit analysis. In this lesson you will learn the rules that govern current and potential difference in DC circuits, how to calculate total resistance for series and parallel combinations, and how to apply the...
3.5.1.5 - Potential DividerIn many circuits we need a specific voltage that is lower than the supply voltage, or a voltage that changes in response to environmental conditions such as temperature or light level. A potential divider is an elegantly simple arrangement of resistors in series that lets us tap off any fraction...
3.5.1.6 - Electromotive Force and Internal ResistanceEvery battery you use -- from the one in your phone to the cells in a physics lab -- wastes some of the energy it produces just pushing charge through itself. This happens because all real sources of electrical energy have internal resistance. Understanding this concept is essential for analysing...
RP06 - EMF and Internal ResistanceEvery battery you buy is labelled with a voltage, yet connect it to a circuit and a voltmeter across its terminals reads something lower. The difference is not a manufacturing error; it is a fundamental consequence of the battery doing work to push charge through its own materials. Required Pract...
Section 6: Further Mechanics and Thermal Physics / 6.1 - Periodic Motion
3.6.1.1 - Circular MotionAny object moving along a curved path is being continuously deflected from a straight line. Whether it is a satellite orbiting the Earth, a car rounding a bend, or a capsule on the London Eye, the physics is the same: an inward force must act at every instant to change the direction of the veloci...
3.6.1.2 - Simple Harmonic MotionSimple harmonic motion (SHM) is one of the most important types of motion in physics. From the swing of a pendulum to the vibration of atoms in a crystal lattice, SHM underpins a vast range of physical phenomena. In this lesson you will learn the defining conditions of SHM, the key equations that...
Section 6: Further Mechanics and Thermal Physics / 6.2 - Thermal Physics
Section 7: Fields and Their Consequences / 7.1 - Fields
Section 7: Fields and Their Consequences / 7.2 - Gravitational Fields
Section 7: Fields and Their Consequences / 7.3 - Electric Fields
Section 7: Fields and Their Consequences / 7.4 - Capacitance
Section 7: Fields and Their Consequences / 7.5 - Magnetic Fields
Section 8: Nuclear Physics / 8.1 - Radioactivity and Nuclear Energy
Optional Sections (your school picks one)
Option A: Astrophysics / A.1 - Telescopes
Option A: Astrophysics / A.2 - Classification of Stars
Option A: Astrophysics / A.3 - Cosmology
Option B: Medical Physics / B.1 - Physics of the Eye
Option B: Medical Physics / B.2 - Physics of the Ear
Option B: Medical Physics / B.3 - Biological Measurement
Option B: Medical Physics / B.4 - Non-Ionising Imaging
Option B: Medical Physics / B.5 - X-Ray Imaging
Option B: Medical Physics / B.6 - Radionuclide Imaging and Therapy
Option C: Engineering Physics / C.1 - Rotational Dynamics
Option C: Engineering Physics / C.2 - Thermodynamics and Engines
Option D: Turning Points in Physics / D.1 - The Discovery of the Electron
Option D: Turning Points in Physics / D.2 - Wave-Particle Duality
Option D: Turning Points in Physics / D.3 - Special Relativity
Option E: Electronics / E.1 - Sensing Devices
Option E: Electronics / E.2 - Signal Processing
Option E: Electronics / E.3 - Filters and Amplifiers
Option E: Electronics / E.4 - Op-Amp Circuits
Option E: Electronics / E.5 - Digital Electronics
Option E: Electronics / E.6 - Communication Systems
Section 3: Waves
3.1 - Progressive and Stationary Waves
Section 4: Mechanics and Materials
4.1 - Force, Energy and Momentum
4.2 - Materials
Section 5: Electricity
5.1 - Current Electricity
Section 6: Further Mechanics and Thermal Physics
6.2 - Thermal Physics
Section 7: Fields and Their Consequences
7.2 - Gravitational Fields
7.5 - Magnetic Fields
Section 8: Nuclear Physics
8.1 - Radioactivity and Nuclear Energy
Option A: Astrophysics
A.1 - Telescopes
A.2 - Classification of Stars
Option B: Medical Physics
B.1 - Physics of the Eye
Option D: Turning Points in Physics
D.1 - The Discovery of the Electron
Option E: Electronics
E.4 - Op-Amp Circuits
E.6 - Communication Systems