Specification points
WJEC A-level Physics A420QS
331 points in 3 topics, with WJEC's codes and titles.
Grade boundaries·WJEC command words
Codes and titles are read by a script from WJEC's published specification and have not been checked by a person. What each point covers is in the specification itself: WJEC’s specification.
C1 Component 1: Newtonian Physics
- C1.1 Basic Physics
- C1.1(a) The 6 essential base SI units (kg, m, s, A, mol, K)
- C1.1(b) SI base units and prefixes
- C1.1(c) Checking equations for homogeneity using units
- C1.1(d) Scalar and vector quantities
- C1.1(e) Adding and subtracting coplanar vectors
- C1.1(f) Resolving vectors into components
- C1.1(g) Density
- C1.1(h) Turning effect of a force
- C1.1(i) The use of the principle of moments
- C1.1(j) Centre of gravity and stability
- C1.1(k) Equilibrium: resultant force and moment
- C1.2 Kinematics
- C1.2(a) Displacement, speed, velocity and acceleration
- C1.2(b) The representation of displacement, speed, velocity and acceleration by graphical methods
- C1.2(c) Displacement-time and velocity-time graphs
- C1.2(d) Equations of uniformly accelerated motion
- C1.2(e) Falling bodies and terminal velocity
- C1.2(f) Independence of vertical and horizontal motion
- C1.2(g) Projectile motion
- C1.3 Dynamics
- C1.3(a) The concept of force and Newton's 3rd law of motion
- C1.3(b) Free body diagrams
- C1.3(c) Newton's second law, F = ma
- C1.3(d) Linear momentum
- C1.3(e) Force as rate of change of momentum
- C1.3(f) Conservation of momentum; elastic and inelastic collisions
- C1.4 Energy Concepts
- C1.4(a) Work done by a force
- C1.4(b) Work done when force is not along the motion
- C1.4(c) Conservation of energy
- C1.4(d) The work–energy relationship
- C1.4(e) Power being the rate of energy transfer
- C1.4(f) Dissipative forces and efficiency
- C1.4(g) Efficiency as a percentage
- C1.5 Circular Motion
- C1.5(a) The terms period of rotation, frequency
- C1.5(b) The definition of the unit radian as a measure of angle
- C1.5(c) The use of the radian as a measure of angle
- C1.5(d) Angular velocity
- C1.5(e) Centripetal force as the resultant force
- C1.5(f) Direction of centripetal force and acceleration
- C1.5(g) Equations of circular motion
- C1.6 Vibrations
- C1.6(a) The definition of simple harmonic motion as a statement in words
- C1.6(b) Defining equation of simple harmonic motion
- C1.6(c) Acceleration–displacement graph in SHM
- C1.6(d) Displacement equation for SHM
- C1.6(e) The terms frequency, period, amplitude and phase
- C1.6(f) Period and frequency of SHM
- C1.6(g) Velocity equation for SHM
- C1.6(h) Displacement and velocity graphs in SHM
- C1.6(i) Period of a mass–spring system
- C1.6(j) Period of a simple pendulum
- C1.6(k) Energy interchange in SHM
- C1.6(l) Free oscillations and the effect of damping in real systems
- C1.6(m) Practical examples of damped oscillations
- C1.6(n) The importance of critical damping in appropriate cases such as vehicle suspensions
- C1.6(o) Forced oscillations and resonance, with practical examples
- C1.6(p) Forced oscillations, damping and resonance curves
- C1.6(q) Uses and dangers of resonance
- C1.7 Kinetic Theory
- C1.7(a) Ideal gas equation
- C1.7(b) Assumptions of the kinetic theory of gases
- C1.7(c) Molecular movement and gas pressure
- C1.7(d) The Avogadro constant and the mole
- C1.7(e) Molar mass and relative molecular mass
- C1.7(f) Kinetic theory and mean molecular kinetic energy
- C1.8 Thermal Physics
- C1.8(a) Internal energy
- C1.8(b) Absolute zero
- C1.8(c) Internal energy of an ideal monatomic gas
- C1.8(d) Heat flow across a boundary
- C1.8(e) Thermal equilibrium
- C1.8(f) Work as energy in transit
- C1.8(g) Work done by a gas at constant pressure
- C1.8(h) Work from the area under a p–V graph
- C1.8(i) First law of thermodynamics
- C1.8(j) Heat and internal energy in solids and liquids
- C1.8(k) Specific heat capacity
C2 Component 2: Electricity and the Universe
- C2.1 Conduction of Electricity
- C2.1(a) Charge and the coulomb
- C2.1(b) Conductors and the flow of charge
- C2.1(c) Electric current being the rate of flow of charge
- C2.1(d) Current equation I = ΔQ/Δt
- C2.1(e) The ampere as one coulomb per second
- C2.1(f) The mechanism of conduction in metals as the drift of free electrons
- C2.1(g) Current and drift velocity, I = nAve
- C2.2 Resistance
- C2.2(a) The definition of potential difference
- C2.2(b) Potential difference and the volt
- C2.2(c) I–V graphs for a filament lamp and a metal wire
- C2.2(d) Ohm's law, the equation V = IR and the definition of resistance
- C2.2(e) The ohm
- C2.2(f) Equations for electrical power
- C2.2(g) Resistance from electron–ion collisions
- C2.2(h) The resistivity equation
- C2.2(i) Resistance of metals and temperature
- C2.2(j) Collisions and heating in metals
- C2.2(k) Superconductivity and transition temperature
- C2.2(l) Superconducting transition temperatures of metals
- C2.2(m) High-temperature superconductors
- C2.2(n) Uses of superconductors
- C2.3 D.C. Circuits
- C2.3(a) Currents in parallel circuits
- C2.3(b) Potential differences in series circuits
- C2.3(c) Potential differences across parallel components
- C2.3(d) Combined resistance in series and parallel
- C2.3(e) Potential dividers
- C2.3(f) Electromotive force of a source
- C2.3(g) The unit of emf
- C2.3(h) Internal resistance
- C2.3(i) Current and potential difference with cells in series
- C2.4 Capacitance
- C2.4(a) Parallel plate capacitors
- C2.4(b) Storing energy by transferring charge between the plates
- C2.4(c) Definition of capacitance
- C2.4(d) Capacitance of a parallel plate capacitor
- C2.4(e) Dielectrics
- C2.4(f) Electric field in a parallel plate capacitor
- C2.4(g) Stored energy equation U = ½QV
- C2.4(h) The equations for capacitors in series and in parallel
- C2.4(i) The process by which a capacitor charges and discharges through a resistor
- C2.4(j) Charging and discharging capacitors
- C2.5 Solids Under Stress
- C2.5(a) Hooke's law and the spring constant
- C2.5(b) Tensile stress, strain and the Young modulus
- C2.5(c) Work done in deforming a solid
- C2.5(d) Crystalline, amorphous and polymeric solids
- C2.5(e) Force-extension graphs for ductile metals
- C2.5(f) Force-extension graphs for brittle materials
- C2.5(g) Force–extension and stress–strain graphs for rubber
- C2.6 Electrostatic and Gravitational Fields of Force
- C2.6(a) Electric and gravitational fields compared
- C2.6(b) Gravitational field outside a spherical body
- C2.6(c) Field lines
- C2.6(d) Equipotential surfaces
- C2.6(e) Net potential and field of several point charges or masses
- C2.6(f) Gravitational potential energy near the surface
- C2.7 Using Radiation to Investigate Stars
- C2.7(a) Stellar spectra
- C2.7(b) Black bodies
- C2.7(c) Black body spectrum and peak wavelength
- C2.7(d) Wien's law, Stefan's law and properties of stars
- C2.7(e) Multiwavelength astronomy
- C2.8 Orbits and the Wider Universe
- C2.8(a) Kepler's three laws of planetary motion
- C2.8(b) Newton's law of gravitation
- C2.8(c) Deriving Kepler's third law
- C2.8(d) Mass of a central object from orbital data
- C2.8(e) Galaxy rotation and dark matter
- C2.8(f) The Higgs boson and dark matter
- C2.8(g) Centre of mass of a two-body system
- C2.8(h) The Doppler relationship
- C2.8(i) Radial velocity of a star
- C2.8(j) Detecting exoplanets from radial velocity data
- C2.8(k) The Hubble constant
- C2.8(l) Hubble time 1/H₀ and the age of the universe
- C2.8(m) Critical density of a flat universe
C3 Component 3: Light, Nuclei and Options
- C3.1 The Nature of Waves
- C3.1(a) Progressive waves and energy transfer
- C3.1(b) The difference between transverse and longitudinal waves
- C3.1(c) The term polarisation
- C3.1(d) The terms in phase and in antiphase
- C3.1(e) The terms displacement, amplitude, wavelength, frequency, period and velocity of a wave
- C3.1(f) Displacement graphs for transverse waves
- C3.1(g) Wave equation c = fλ
- C3.1(h) Wavefronts, phase and rays
- C3.2 Wave Properties
- C3.2(a) Diffraction occuring when waves encounter slits or obstacles
- C3.2(b) Little diffraction at large gaps
- C3.2(c) Diffraction and slit width
- C3.2(d) Two-source interference
- C3.2(e) The historical importance of Young’s experiment
- C3.2(f) The principle of superposition, giving appropriate sketch graphs
- C3.2(g) Path difference and interference
- C3.2(h) Young's double slit equation
- C3.2(i) The diffraction grating equation
- C3.2(j) Diffraction gratings compared with Young's slits
- C3.2(k) Coherent sources
- C3.2(l) Examples of coherent and incoherent sources
- C3.2(m) Conditions for observing two-source interference
- C3.2(n) The differences between stationary and progressive waves
- C3.2(o) Stationary waves as superposition
- C3.3 Refraction of Light
- C3.3(a) Refractive index
- C3.3(b) Snell's law
- C3.3(c) Snell's law and the wave model of light
- C3.3(d) The conditions for total internal reflection
- C3.3(e) Critical angle
- C3.3(f) Total internal reflection in multimode fibres
- C3.3(g) Multimode dispersion in optical fibres
- C3.3(h) Monomode optical fibres
- C3.4 Photons
- C3.4(a) Photons as packets of energy
- C3.4(b) Demonstrating the photoelectric effect
- C3.4(c) Measuring maximum kinetic energy with a vacuum photocell
- C3.4(d) Graph of maximum kinetic energy against frequency
- C3.4(e) Einstein's photoelectric equation
- C3.4(f) The electromagnetic spectrum
- C3.4(g) Typical photon energies for these radiations
- C3.4(h) Producing line emission and absorption spectra
- C3.4(i) The appearance of such spectra as seen in a diffraction grating
- C3.4(j) Energy level diagrams and line spectra
- C3.4(k) Ionisation energies from energy level diagrams
- C3.4(l) Electron diffraction and wave-particle duality
- C3.4(m) The de Broglie relationship
- C3.4(n) The calculation of radiation pressure on a surface absorbing or reflecting photons
- C3.5 Lasers
- C3.5(a) Stimulated emission
- C3.5(b) Population inversion in lasers
- C3.5(c) Population inversion and two-level systems
- C3.5(d) Population inversion in three- and four-level systems
- C3.5(e) The process of pumping and its purpose
- C3.5(f) Structure of a laser
- C3.5(g) Semiconductor lasers: advantages and uses
- C3.6 Nuclear Decay
- C3.6(a) Nuclear decay and alpha, beta and gamma radiation
- C3.6(b) Distinguishing alpha, beta and gamma radiation
- C3.6(c) Background radiation
- C3.6(d) The concept of the half-life, T½
- C3.6(e) The definition of the activity, A, and the Becquerel
- C3.6(f) The decay constant and activity, A = λN
- C3.6(g) The exponential law of radioactive decay
- C3.6(h) Half-life and the decay constant
- C3.7 Particles and Nuclear Structure
- C3.7(a) Rutherford scattering experiment
- C3.7(b) Coulomb repulsion in alpha scattering
- C3.7(c) Quarks and leptons
- C3.7(d) Antiparticles
- C3.7(e) Symbols for a positron and for antiparticles of quarks and hadrons
- C3.7(f) Hadrons, baryons and mesons
- C3.7(g) The quark compositions of the neutron and proton
- C3.7(h) Quark make-up of baryons and pions
- C3.7(i) The four fundamental forces
- C3.7(j) Conservation laws in particle reactions
- C3.7(k) Weak interactions: neutrinos and quark flavour changes
- C3.8 Nuclear Energy
- C3.8(a) Mass–energy equivalence, E = mc²
- C3.8(b) Binding energy per nucleon
- C3.8(c) Calculating binding energy
- C3.8(d) Conservation of mass-energy in fission and fusion
- C3.8(e) Binding energy per nucleon in fission and fusion
- C3.9 Magnetic Fields
- C3.9(a) Direction of force on a current-carrying conductor
- C3.9(b) Magnetic field strength from the force on a conductor
- C3.9(c) Force on a moving charge in a magnetic field
- C3.9(d) The Hall voltage
- C3.9(e) Magnetic fields of a wire and a solenoid
- C3.9(f) Field strength of a wire and a solenoid
- C3.9(g) Iron cores in solenoids
- C3.9(h) Forces between current-carrying conductors
- C3.9(i) Deflection of ion beams in electric and magnetic fields
- C3.9(j) Particle accelerators
- C3.10 Electromagnetic Induction
- C3.10(a) Magnetic flux and flux linkage
- C3.10(b) The laws of Faraday and Lenz
- C3.10(c) Applying Faraday's and Lenz's laws: emf and flux linkage
- C3.10(d) Emf induced in a moving conductor
- C3.10(e) Emf induced in a rotating coil
- C3.A Option A: Alternating Currents
- C3.A(a) Faraday's law applied to a rotating coil
- C3.A(b) Flux linkage of a rotating coil
- C3.A(c) The emf equation V = ωBAN sin ωt for a rotating coil
- C3.A(d) Frequency, period, peak and rms values
- C3.A(e) RMS values and energy dissipated
- C3.A(f) Mean power in a resistor
- C3.A(g) Measuring a.c. with an oscilloscope
- C3.A(h) Phase lag in an inductor
- C3.A(i) Inductive reactance
- C3.A(j) Phase lead in a capacitor
- C3.A(k) Mean power in inductors and capacitors
- C3.A(l) Phasors for RC, RL and RCL circuits
- C3.A(m) Phase angle and impedance
- C3.A(n) Resonance frequency of an RCL circuit
- C3.A(o) Q factor of an RCL circuit
- C3.A(p) Q factor and sharpness of resonance
- C3.B Option B: Medical Physics
- C3.B(a) The nature and properties of X-rays
- C3.B(b) Production of X-ray spectra
- C3.B(c) X-rays in therapy and diagnosis
- C3.B(d) Attenuation of X-rays
- C3.B(e) X-ray imaging of soft tissue and fluoroscopy
- C3.B(f) Techniques of radiography including using digital image receptors
- C3.B(g) The use of a rotating beam X-ray computed tomography (CT) scanner
- C3.B(h) The generation and detection of ultrasound using piezoelectric transducers
- C3.B(i) Ultrasound A-scans and B-scans
- C3.B(j) Acoustic impedance
- C3.B(k) Doppler ultrasound and blood flow
- C3.B(l) Principles of magnetic resonance imaging
- C3.B(m) The use of MRI in obtaining diagnostic information about internal structures
- C3.B(n) Comparing ultrasound, X-ray imaging and MRI
- C3.B(o) The effects of α, β, and γ radiation on living matter
- C3.B(p) Absorbed, equivalent and effective dose
- C3.B(q) Equivalent and effective dose equations
- C3.B(r) Radionuclides as tracers; technetium-99m
- C3.B(s) The gamma camera
- C3.B(t) Positron emission tomography (PET) scanning and its use in detecting tumours
- C3.C Option C: The Physics of Sports
- C3.C(a) Centre of gravity, stability and toppling in sport
- C3.C(b) Principle of moments in the body
- C3.C(c) Impulse and momentum in sport
- C3.C(d) The coefficient of restitution
- C3.C(e) Moment of inertia
- C3.C(f) Calculating moment of inertia
- C3.C(g) Angular acceleration
- C3.C(h) Torque
- C3.C(i) Angular momentum
- C3.C(j) Conservation of angular momentum in sport
- C3.C(k) Rotational kinetic energy
- C3.C(l) Conservation of energy in sport
- C3.C(m) Projectile motion in sport
- C3.C(n) Bernoulli's equation in sport
- C3.C(o) Drag force and drag coefficient
- C3.D Option D: Energy and the Environment
- C3.D(a) Factors affecting the Earth's temperature rise
- C3.D(a)(i) Thermal equilibrium of the Earth
- C3.D(a)(ii) Solar energy and the Sun's power spectrum
- C3.D(a)(iii) Wien's and Stefan's laws and solar power
- C3.D(a)(iv) Melting ice and rising sea levels
- C3.D(b) Renewable and non-renewable energy sources
- C3.D(b)(i) Solar power
- C3.D(b)(ii) Wind power
- C3.D(b)(iii) Tidal barrages, hydroelectric power and pumped storage
- C3.D(b)(iv) Nuclear fission and fusion
- C3.D(c) Fuel cells
- C3.D(d) Thermal conduction equation
- C3.D(e) Insulation and thermal energy loss