# WJEC A-level Physics revision: every topic by unit > Every WJEC A-level Physics topic, how often it came up in the 2022–2025 papers, and the common errors to avoid. Free, with honest coverage. Canonical: https://revise-gray.vercel.app/wjec-a-level-physics Every topic in WJEC AS and A level Physics, ranked by how often the 2022–2025 papers examined it, with the common errors to avoid. ## How the course is examined The written papers cover 4 units: 2 at AS and 2 at A2. Revise has indexed every question from 16 papers sat in 2022–2025, 126 questions in all. - **Unit 1** (AS): Motion, Energy and Matter - **Unit 2** (AS): Electricity and Light - **Unit 3** (A2): Oscillations and Nuclei - **Unit 4** (A2): Fields and Options - Unit 4 ends with a choice of option; you answer one: Alternating currents and AC circuits, Energy and the environment, Medical physics, The physics of sport. ## Every topic, most examined first How often each topic has come up in 2022–2025. A question can assess more than one topic, so marks overlap between rows. | Topic | Years examined | Questions | Marks | Units | | --- | --- | --- | --- | --- | | [Practical investigations and data analysis](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.practical-investigations) | 4 of 4 | 17 | 223 | 1, 2, 3, 4 | | [Gravitational, electric and magnetic fields](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.fields) | 4 of 4 | 15 | 218 | 3, 4 | | [Nuclear and particle physics](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.nuclear) | 4 of 4 | 13 | 156 | 1, 3 | | [Waves, superposition and optics](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.waves) | 4 of 4 | 14 | 137 | 2 | | [Thermal physics and gases](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.thermal) | 4 of 4 | 9 | 134 | 3 | | [Circular motion and simple harmonic motion](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.circular-shm) | 4 of 4 | 9 | 131 | 3 | | [Electric circuits](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.electric-circuits) | 4 of 4 | 10 | 107 | 2 | | [Motion, forces and Newton's laws](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.kinematics-dynamics) | 4 of 4 | 8 | 107 | 1 | | [Photons and the photoelectric effect](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.quantum) | 4 of 4 | 10 | 96 | 2, 3 | | [Orbits and the wider universe](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.orbits-universe) | 4 of 4 | 6 | 91 | 3, 4 | | [Solids under stress](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.materials) | 4 of 4 | 7 | 72 | 1 | | [Capacitance and RC circuits](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.capacitance) | 4 of 4 | 5 | 59 | 4 | | [Momentum and collisions](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.momentum) | 4 of 4 | 4 | 54 | 1 | | [Alternating currents and AC circuits](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.alternating-currents) | 3 of 4 | 3 | 60 | 4 | | [Energy and the environment](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.energy-environment) | 3 of 4 | 3 | 60 | 4 | | [Medical physics](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.medical-physics) | 3 of 4 | 3 | 60 | 4 | | [The physics of sport](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.sports-physics) | 3 of 4 | 3 | 60 | 4 | | [Electromagnetic induction and transformers](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.electromagnetic-induction) | 3 of 4 | 3 | 29 | 4 | | [Energy, work and power](https://revise-gray.vercel.app/library?topic=wjec-alevel-physics.energy-power) | 2 of 4 | 2 | 22 | 1 | ## What each topic covers ### Motion, forces and Newton's laws Scalars and vectors, motion graphs, the equations of motion, Newton's three laws, free-body diagrams and projectile motion. - Common error: Treating weight and the normal contact force as a Newton's third law pair. - Common error: Forgetting that a body at terminal velocity has zero resultant force, not zero force. - Common error: Mixing up distance and displacement for motion that reverses. ### Energy, work and power Work done by a force, kinetic and gravitational potential energy, conservation of energy, power and efficiency, including work from a force–displacement graph. - Common error: Omitting cosθ when the force is at an angle. - Common error: Quoting an efficiency above 100% after a unit slip. - Common error: Saying energy is 'lost' rather than dissipated, usually as heat. ### Solids under stress Hooke's law, the spring constant, stress, strain and the Young modulus, elastic and plastic behaviour, and energy stored in a stretched material. - Common error: Using diameter instead of radius in the cross-sectional area. - Common error: Reading the Young modulus off a force–extension rather than a stress–strain graph. - Common error: Confusing the elastic limit with the yield point. ### Waves, superposition and optics Transverse and longitudinal waves, the wave equation, refraction and total internal reflection, polarisation, superposition, stationary waves and diffraction gratings. - Common error: Saying wavelength stays the same on refraction (it is frequency that does). - Common error: Mixing up slit separation and grating spacing d = 1/N. - Common error: Describing a node as a point of maximum displacement. ### Photons and the photoelectric effect The photon model, the photoelectric equation, work function and threshold frequency, wave–particle duality and de Broglie wavelength, and atomic energy levels. - Common error: Saying brighter light gives faster electrons. - Common error: Forgetting to convert eV to joules (1 eV = 1.6 × 10⁻¹⁹ J). - Common error: Using the work function as an energy per mole. ### Electric circuits Current, potential difference and resistance, Kirchhoff's laws, resistivity, EMF and internal resistance, potential dividers, and the I–V characteristics of components. - Common error: Treating EMF and terminal p.d. as identical. - Common error: Using length in cm in a resistivity calculation. - Common error: Adding parallel resistances directly. ### Momentum and collisions Linear momentum, impulse, conservation of momentum in one and two dimensions, and elastic versus inelastic collisions. - Common error: Assuming kinetic energy is conserved in every collision. - Common error: Dropping the direction sign for a rebounding object, halving the calculated impulse. - Common error: Using speed rather than velocity components in 2D problems. ### Circular motion and simple harmonic motion Angular velocity, centripetal acceleration and force, the conditions for SHM, displacement/velocity/acceleration relationships, energy in SHM, damping and resonance. - Common error: Adding 'centripetal force' to a free-body diagram as if it were a separate force. - Common error: Losing the minus sign in a = −ω²x and so the direction of acceleration. - Common error: Using degrees for ω in radian-based formulae. ### Gravitational, electric and magnetic fields Newton's law of gravitation and Coulomb's law, field strength and potential, orbits, the motion of charges in magnetic fields, electromagnetic induction and Faraday's and Lenz's laws. - Common error: Forgetting that gravitational potential is negative everywhere. - Common error: Using r as height above the surface instead of distance from the centre. - Common error: Omitting the minus sign or the opposition statement when quoting Lenz's law. ### Thermal physics and gases Internal energy, specific heat capacity and latent heat, the ideal gas laws, kinetic theory and the link between temperature and mean molecular kinetic energy. - Common error: Working in °C in a gas law. - Common error: Applying Q = mcΔT during melting or boiling. - Common error: Saying 'heat' when internal energy or temperature is meant. ### Nuclear and particle physics Rutherford scattering, nuclear radius, radioactive decay and half-life, mass–energy equivalence, fission and fusion, and the quark model of hadrons. - Common error: Using half-life in the exponential formula without converting to the decay constant. - Common error: Forgetting the antineutrino in β⁻ decay and breaking lepton-number conservation. - Common error: Confusing binding energy with binding energy per nucleon when comparing nuclei. ### Capacitance and RC circuits Charge storage, energy in a capacitor and the exponential charge/discharge of an RC circuit, including how to read the time constant from data. - Common error: Using the resistor-current equation alone and forgetting that capacitor current changes during the transient. - Common error: Adding series capacitances as if they were resistors in parallel. - Common error: Calling τ the time to reach the final value; it is the characteristic scale, not an instant finish. ### Alternating currents and AC circuits Sinusoidal voltage, rms values, phase and impedance: why capacitors, inductors and transformers behave differently at different frequencies. - Common error: Using peak voltage in a mains-power calculation that requires rms voltage. - Common error: Saying a transformer changes frequency as well as voltage; the frequency is set by the supply. - Common error: Calling resonance the point of minimum current in a series RLC circuit. ### Medical physics X-ray, ultrasound, MRI and radionuclide imaging: how each modality forms contrast and the safety trade-offs behind a diagnosis. - Common error: Calling ultrasound electromagnetic radiation; it is a mechanical longitudinal wave. - Common error: Saying MRI uses X-rays; its signal comes from nuclear spins and radiofrequency pulses. - Common error: Assuming higher image contrast is always better when it may require a higher patient dose. ### The physics of sport Applying mechanics, energy, impulse and fluid ideas to sporting motion while separating a useful model from the messy real system. - Common error: Assuming horizontal velocity is constant when drag is significant. - Common error: Using the distance from the joint rather than the perpendicular distance to a force line when taking moments. - Common error: Confusing impulse with kinetic energy. ### Energy and the environment Comparing energy resources and storage by efficiency, power, emissions, reliability and life-cycle impact rather than by a single headline number. - Common error: Calling an energy source 100% efficient because the fuel is free or renewable. - Common error: Treating power and energy as interchangeable. - Common error: Counting only operational emissions and ignoring construction or disposal stages. ### Practical investigations and data analysis Planning, measuring, graphing and evaluating a physics investigation so that a conclusion follows from evidence rather than from a neat-looking line. - Common error: Saying repeats remove systematic error. - Common error: Drawing a best-fit line through the origin without evidence that the intercept is zero. - Common error: Calling a result precise because the graph is smooth while ignoring a large scale uncertainty. ### Orbits and the wider universe Using gravitational fields to explain satellite orbits, then connecting redshift, the Hubble law and standard-candle evidence to an expanding universe. - Common error: Using the radius above the surface instead of distance from the centre of the attracting body. - Common error: Saying a satellite needs a continuous tangential force to keep moving in orbit; gravity changes its direction of velocity. - Common error: Treating redshift alone as a direct measurement of distance without explaining the Hubble-law model and its uncertainties. ### Electromagnetic induction and transformers Explaining induced emf with magnetic flux, Faraday's law and Lenz's law, then applying the model to generators, transformers and efficient power transmission. - Common error: Using the magnetic field itself rather than the rate of change of flux when deciding whether an emf is induced. - Common error: Quoting Lenz's law as 'the current opposes the motion' without identifying the change in flux it opposes. - Common error: Assuming a transformer works with steady direct current; changing magnetic flux is required and the windings must share a changing field. ## Examined, but not yet a topic in Revise The papers examine this content and Revise has no topic for it yet. Revise it from your textbook. - Radiation from stars: black body, Wien, Stefan and inverse-square intensity: 5 questions in 2022–2025 - Moments, centre of gravity and equilibrium: 5 questions in 2022–2025 ## What Revise covers today > Four WJEC A-level subjects (Mathematics, Biology, Chemistry and Physics) have their topics and specification statements authored. No question has been through human review yet, so Revise cannot yet prove that a learner has improved. Other boards and qualifications reuse those outlines and are labelled reference material. > Lessons are written for 108 of the 108 Physics specification statements in Revise. They are not yet teacher-reviewed. Which topics each past-paper question assesses is Revise's own classification and is not reviewed either. ## Revise it [Open Revise](https://revise-gray.vercel.app/) to get the one most useful thing to do next, spaced repetition for what you are about to forget, and exam-style questions marked point by point. It is free, needs no account and keeps your work on your device. Then practise with [past paper questions by topic](https://revise-gray.vercel.app/wjec-a-level-physics/past-papers), learn the [definitions](https://revise-gray.vercel.app/wjec-a-level-physics/definitions) and check the [data booklet constants](https://revise-gray.vercel.app/wjec-a-level-physics/data-booklet). ## Related - [Past paper questions by topic](https://revise-gray.vercel.app/wjec-a-level-physics/past-papers) - [Definitions](https://revise-gray.vercel.app/wjec-a-level-physics/definitions) - [Data booklet](https://revise-gray.vercel.app/wjec-a-level-physics/data-booklet) - [What Revise can and cannot do yet](https://revise-gray.vercel.app/welcome)