Key term
WJEC A-Level Physics 1420QS
Basic Physics
Kinematics
Dynamics
Energy Concepts
Solids Under Stress
Using Radiation to Investigate Stars
Particles and Nuclear Structure
Topic overviewQuarks, leptons and hadronsThe four interactions and conservation lawsThe first generation of quarks and leptonsAntiparticles and annihilationBaryons, antibaryons and mesonsDeducing quark compositions from chargeBeta decay and quark flavour changeTesting a reaction against the conservation rules
Conduction of Electricity
Resistance
Topic overviewCalculating resistance from resistivityPotential difference, Ohm's law and powerResistivity, temperature and superconductivityThe volt: energy transferred per unit chargeCurrent–voltage characteristics of non-ohmic componentsMeasuring resistance and resistivity in the laboratoryThe heating effect of a current and choosing a power equationThermistors and how a semiconductor's resistance falls with temperatureConductance, conductivity and comparing materials
D.C. Circuits
Topic overviewKirchhoff's laws, and resistors in series and parallelPotential dividers, emf and internal resistanceCells, resistivity, power and energyWorking out currents and potential differences in resistor networksSensor circuits with thermistors and LDRsInternal resistance, power transfer and short-circuit currentAmmeters, voltmeters and their effect on the circuit
The Nature of Waves
Wave Properties
Topic overviewEnergy transfer and the wave equationTransverse and longitudinal waves, path difference and intensityDiffraction and superpositionTwo-source interference and the diffraction gratingStationary wavesHow much a wave spreads at a gap or an obstacleCoherence and the conditions for observable interferenceYoung's double slit and λ = ay/DMeasuring wavelength with a diffraction gratingMeasuring the speed of sound with stationary waves
Refraction of Light
Photons
Topic overviewPhoton energy and the electronvoltThe photoelectric effectStopping potential and the Planck constantThe photoelectric effect and photon energiesLine spectra and energy levelsDemonstrating the photoelectric effectThe electromagnetic spectrum and typical photon energiesElectron diffraction and the de Broglie relationshipRadiation pressure
Lasers
Circular Motion
Vibrations
Topic overviewSimple harmonic motion and its equationsOscillating systems and energyDamping and resonanceThe simple pendulumThe mass–spring oscillatorThe displacement and velocity equationsGraphs of displacement, velocity and accelerationThe energy interchange in simple harmonic motionFree and forced oscillationsLight, heavy and critical damping
Kinetic Theory
Thermal Physics
Topic overviewInternal energy and heatWork, the first law and specific heat capacityThermal equilibrium, temperature and absolute zeroThe internal energy of an ideal monatomic gasWork done by a gas at constant pressureThe p–V diagram and work as an areaSign conventions and special cases of the first lawMeasuring specific heat capacity
Nuclear Decay
Nuclear Energy
Capacitance
Topic overviewCapacitance and the parallel plate capacitorEnergy, combinations and RC circuitsCharging at constant current and measuring capacitanceDielectrics and relative permittivityThe uniform field between capacitor platesEnergy stored in a capacitor and the Q–V graphExponential discharge, the time constant and log graphsCapacitors in series and parallel: charge and potential difference sharing
Electrostatic and Gravitational Fields of Force
Topic overviewElectric and gravitational fields comparedField lines, equipotentials and combining fieldsElectric potential and the work done on a chargeGravitational potential and potential energyAdding potentials and fields from several sourcesEquipotential surfacesComparing the two fields point by point
Orbits and the Wider Universe
Topic overviewKepler's laws and orbital motionThe Doppler effect, dark matter and the expanding universeNewton's law of gravitation applied to orbitsDeriving Kepler's third lawFinding the mass of a central objectGalactic rotation curves and dark matterThe centre of mass of a two-body systemRadial velocity and the Doppler shift of spectral linesHubble's law and the age of the universe
Magnetic Fields
Topic overviewMagnetic fields and field patternsMagnetic flux density and the force on a conductorThe force on a moving charge and its circular pathThe Hall effect and the Hall voltageMagnetic fields due to a current in a wire and in a solenoidForces between current-carrying conductorsCharged particle beams, velocity selectors and accelerators
Electromagnetic Induction
Option A: Alternating CurrentsOption A
Option B: Medical PhysicsOption B
Topic overviewMedical physicsUltrasound imagingRadiation and living tissueX-ray production and beam controlAttenuation and half-value thicknessRadiography, fluoroscopy and CT scanningAcoustic impedance and ultrasound reflectionMagnetic resonance imagingAbsorbed dose, equivalent dose and effective doseRadionuclide tracers, the gamma camera and PET
Option C: The Physics of SportsOption C
Topic overviewCentre of gravity, stability and momentsRestitution, moment of inertia and angular momentumRotational energy, projectiles and the flight of a ballMoments in the muscles and jointsApplying the impulse equation in sportMoment of inertia and angular kinematicsTorque, angular momentum and its conservationRotational energy and energy conservation in sport
Option D: Energy and the EnvironmentOption D
Topic overviewFactors affecting the rate at which the temperature of the Earth risesThe Earth's thermal equilibrium, Wien's law and Stefan's lawRenewable and non-renewable sourcesSolar energy and photovoltaic cellsWind, tidal and hydroelectric powerNuclear fission and fusion as energy sourcesU-values and rates of heat lossFuel cells and how they workFuel cells: benefits, limitations and the hydrogen economyThermal conduction, conductivity and insulation
Mathematical Requirements (Appendix C)
Topic overviewSignificant figures and arithmetic meansUncertainty and how uncertainties combineAlgebraic symbols and proportionalityRearranging and solving equationsSmall angle approximationsTangents and instantaneous rates of changeAreas under curves and numerical methodsReading a tangent on a motion graphStraight-line graphs and y = mx + cWhat a gradient and an intercept representLinearising a relationship to find a constantLog plots of exponential decayChoosing what to plot to find a constantLogarithmic scales and orders of magnitudeWorking with base-ten logarithmsThe shapes of common graphsInverse and root relationships on a graphAreas, volumes and PythagorasGeometry applied to physical situationsSubstituting into physical equationsTrigonometry and right-angled trianglesResolving a force into componentsRadians, arc length and force diagramsRandom processes and translating between representationsMean values and periodic functionsSymbols for approximation and comparison
Mathematical Requirements (Appendix C)
- 26 subtopics
- 81 things to know
- All units
What Mathematical Requirements (Appendix C) covers
The mathematical requirements are assessed across every unit of WJEC Physics rather than in a unit of their own. 436 recall questions across 26 subtopics.
Where it is assessed
All units
The mathematical requirements, assessed throughout.
Check the WJEC specification ↗The 26 subtopics
Each one has its own page.
- Significant figures and arithmetic meansRecall questions on Significant figures and arithmetic means.Open →
- Uncertainty and how uncertainties combineRecall questions on Uncertainty and how uncertainties combine.Open →
- Algebraic symbols and proportionalityRecall questions on Algebraic symbols and proportionality.Open →
- Rearranging and solving equationsRecall questions on Rearranging equations and solving equations.Open →
- Small angle approximationsThe small-angle approximations sin θ ≈ θ, tan θ ≈ θ and cos θ ≈ 1 in radians, why they fail in degrees or at larger angles, and their use for pendulums, diffraction and interference fringes.Open →
- Tangents and instantaneous rates of changeRecall questions on Tangents and instantaneous rates of change.Open →
- Areas under curves and numerical methodsRecall questions on Areas under curves and numerical methods.Open →
- Reading a tangent on a motion graphRecall questions on Reading a tangent on a motion graph.Open →
- Straight-line graphs and y = mx + cRecall questions on Straight-line graphs and y = mx + c.Open →
- What a gradient and an intercept representRecall questions on What a gradient and an intercept represent.Open →
- Linearising a relationship to find a constantRecall questions on Linearising a relationship to find a constant.Open →
- Log plots of exponential decayRecall questions on Log plots of exponential decay.Open →
- Choosing what to plot to find a constantRecall questions on Choosing what to plot to find a constant.Open →
- Logarithmic scales and orders of magnitudeRecall questions on Logarithmic scales and orders of magnitude.Open →
- Working with base-ten logarithmsRecall questions on Working with base-ten logarithms.Open →
- The shapes of common graphsRecall questions on The shapes of common graphs.Open →
- Inverse and root relationships on a graphRecall questions on Inverse and root relationships on a graph.Open →
- Areas, volumes and PythagorasRecall questions on Areas, volumes and Pythagoras.Open →
- Geometry applied to physical situationsRecall questions on Geometry applied to physical situations.Open →
- Substituting into physical equationsRecall questions on Substituting into physical equations.Open →
- Trigonometry and right-angled trianglesRecall questions on Trigonometry and right-angled triangles.Open →
- Resolving a force into componentsRecall questions on Resolving a force into components.Open →
- Radians, arc length and force diagramsRecall questions on Radians, arc length and force diagrams.Open →
- Random processes and translating between representationsRecall questions on Random processes and translating between representations.Open →
- Mean values and periodic functionsRecall questions on Mean values and periodic functions.Open →
- Symbols for approximation and comparisonRecall questions on Symbols for approximation and comparison.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
List all eight mathematical symbols commonly used in physics that you should recognise.
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How does the kinematic equation v = u + at compare with the linear equation y = mx + c?
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State the thermal conduction equation that relates the rate of heat transfer to the properties of a material and the temperature gradient.
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When using a calculator for exponential functions, what key operations might you need?
Numbers
State the formula for the volume of a rectangular block.
Numbers
What equation would you use to calculate the power available from wind passing through a turbine?
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Define each term in the momentum equation p = mv.
Numbers
State the equation used to calculate momentum from mass and velocity.
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State the kinematic relationship used to analyse a distance–time plot for a freely falling object.
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When raw data values have different numbers of significant figures, how do you determine the appropriate number of significant figures for your final answer?
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Why is a long, thin wire preferred in a Young modulus experiment?
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How do you determine the uncertainty in a quantity calculated by addition or subtraction?
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If a physicist writes that the mass of an electron is << the mass of a proton, what relationship are they expressing?
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If you write F ∝ a, what relationship between force and acceleration are you expressing?
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How do you eliminate a square root when rearranging an equation?
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For small angles measured in radians, what value does cos θ approximate to?
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Explain why cos θ ≈ 1 is valid for small angles.
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What is a tangent to a curve at a point?
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How do you find the instantaneous velocity at a specific time from a displacement-time graph?
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When analysing a displacement–time curve, what must you draw at the point of interest to find the instantaneous velocity?
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After drawing a tangent to a displacement–time curve at a point, what calculation do you perform to find the velocity?
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In what direction does the velocity of an object in circular motion act at any instant?
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What would happen to an object in circular motion if the centripetal force were suddenly removed?
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State the relationship between Young modulus, stress and strain.
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What type of relationship does the equation y = mx + c represent?
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What two key features can be determined from a linear graph?
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For capacitor discharge, what transformation must be applied to voltage readings before plotting to obtain a straight line?
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What does the gradient of a ln V against time graph represent for capacitor discharge?
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Define angular velocity and state its SI unit.
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What type of graph is obtained when ln(N) is plotted against time?
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In projectile motion, what equation relates distance fallen to time, and what does the gradient of a distance versus time-squared graph represent?
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What is the purpose of using logarithms for quantities that span several orders of magnitude?
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State the relationship between a number x, its base-10 logarithm y, and powers of 10.
Process
Describe the process of converting a value to a logarithmic scale.
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Describe the shape of a graph representing y = kx².
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Describe the shape of a graph representing y = sin x.
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Describe how y changes as x increases for the relationship y = k/x.
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Describe the shape of the curve y = k/x² and its behaviour as x increases.
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What are the interior angles in a regular 2D hexagon?
Numbers
Calculate the area of triangle when base = 3.7 m, height = 3.7 m.
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Define sin θ in terms of the sides of a right-angled triangle.
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What is the relationship between degrees and radians?
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State the expression for the horizontal component of a force F acting at angle θ to the horizontal.
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In a right-angled triangle, how is the sine of an angle defined?
Numbers
Calculate the angle in degrees when angle in radians = 6.15 rad.
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In a right-angled triangle, how is sin θ defined?
Numbers
Calculate the mean when sum of readings = 364.7, number of readings = 4.
Numbers
Calculate the acceleration when change in velocity = 38.5 m s⁻¹, change in time = 10 s.
Numbers
State the formula for mean velocity.
Numbers
Calculate the cross-sectional area when radius = 0.003 m.
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On the Richter scale, what does an increase of one whole number represent in terms of measured amplitude?
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Which mathematical symbol would you use to indicate that two values are nearly but not exactly the same?
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If you wanted to express that one quantity is vastly larger than another, which symbol would you use?
Numbers
State the formula for calculating the arithmetic mean of repeated experimental readings.
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How do you determine the uncertainty in a quantity calculated by multiplication or division?
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What does the expression F = Δp/Δt mean in words?
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Describe the general method for solving a linear kinematic equation like v = u + at for an unknown quantity.
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Why would using degrees instead of radians cause small angle approximations to give incorrect results?
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How do you find the instantaneous rate of change at a point on a curved graph?
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How does the method for finding instantaneous rate of change differ from that for mean rate of change on a graph?
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After identifying the correct point on a curved displacement-time graph, what type of line must you draw to find instantaneous velocity?
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In the equation y = mx + c, what do m and c represent?
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How can you use a logarithmic plot to test for an exponential relationship?
Numbers
How do you calculate the time constant τ from the gradient of a ln V against time graph?
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What is the gradient of a ln(N) against time graph?
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For capacitor discharge, what is the equation relating ln V to time, and what does the gradient represent?
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How does a logarithmic scale differ from a linear scale in representing changes?
Numbers
Calculate the logarithm of value when value = 977222.
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Describe the shape of a graph representing y = cos x.
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Describe the shape of the curve y = k√x.
Numbers
Calculate the area of circle when radius = 1.82 m.
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What assumption does kinetic theory make about the volume of gas particles compared to the container?
Numbers
Calculate the momentum when mass = 75 kg, velocity = 6.5 m s⁻¹.
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How do you convert an angle from degrees to radians?
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What ratio of sides in a right-angled triangle gives the cosine of an angle?
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In a right-angled triangle, how is cos θ defined?
Process
What three stages are involved when working with electrical circuits in practical work?
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Explain why instantaneous velocity differs from mean velocity.
Numbers
State the formula that defines pH in terms of hydrogen ion concentration.
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What is the y-intercept of a linear graph?
Take Mathematical Requirements (Appendix C) further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Absolute uncertainty vs Percentage uncertainty
Absolute uncertainty: the spread in a measurement quoted in the same units as the measurement itself. Percentage uncertainty: that same spread written as a fraction of the measured value and multiplied by a hundred.
A tangent vs A chord
A tangent: a straight line touching a curve at a single point, giving the rate of change at that instant. A chord: a straight line joining two points on a curve, giving the average rate of change between them.
A logarithmic scale vs A linear scale
A logarithmic scale: one on which equal steps stand for equal multiplying factors, so a wide range of sizes fits on one axis. A linear scale: one on which equal steps stand for equal differences, so the spacing is the same everywhere.
Questions from this topic
Each one with the model answer underneath.
- 1
Why must calculated results be reported to the number of significant figures of the least accurate measurement used?
Model answer
Because the final result cannot be more precise than the least precise measurement that contributed to it; reporting more figures would imply false precision.
- 2
When raw data values have different numbers of significant figures, how do you determine the appropriate number of significant figures for your final answer?
Model answer
Round the final answer to match the smallest number of significant figures present in any of the raw data values.
- 3
State the formula for calculating the arithmetic mean of repeated experimental readings.
Model answer
The arithmetic mean equals the sum of all readings divided by the number of readings: x̄ = Σxᵢ / n.
- 4
Define each term in the formula for arithmetic mean: x̄ = Σxᵢ / n
Model answer
x̄ is the arithmetic mean, Σxᵢ is the sum of all individual readings, and n is the total number of readings.
- 5
State the rule for combining uncertainties when two readings are added together.
Model answer
The absolute uncertainties are added together to give the total uncertainty: Δ(A+B) = ΔA + ΔB.
- 6
Why are absolute uncertainties added when combining measurements by addition?
Model answer
Because the worst-case total error occurs when both individual errors act in the same direction, so the maximum possible deviation is the sum of both uncertainties.
What is inside Levo
Six ways to work the same material.
Mathematical Requirements (Appendix C) revision questions
- What does Mathematical Requirements (Appendix C) cover in WJEC A-Level Physics?
- 26 subtopics: significant figures and arithmetic means, uncertainty and how uncertainties combine, algebraic symbols and proportionality, rearranging and solving equations, small angle approximations, tangents and instantaneous rates of change, areas under curves and numerical methods, reading a tangent on a motion graph, straight-line graphs and y = mx + c, what a gradient and an intercept represent, linearising a relationship to find a constant, log plots of exponential decay, choosing what to plot to find a constant, logarithmic scales and orders of magnitude, working with base-ten logarithms, the shapes of common graphs, inverse and root relationships on a graph, areas, volumes and pythagoras, geometry applied to physical situations, substituting into physical equations, trigonometry and right-angled triangles, resolving a force into components, radians, arc length and force diagrams, random processes and translating between representations, mean values and periodic functions and symbols for approximation and comparison. Each one has its own page with questions and model answers.
- How is Mathematical Requirements (Appendix C) organised?
- By the WJEC 1420QS specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Mathematical Requirements (Appendix C), 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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