WJEC A-level Physics revision

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.

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

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