Numbers
WJEC AS-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
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
Solids Under Stress
- 6 subtopics
- 18 things to know
- AS Unit 1
What Solids Under Stress covers
Solids Under Stress is examined on AS Unit 1 of WJEC Physics, Motion, Energy and Matter. 82 recall questions across 6 subtopics.
The 6 subtopics
Each one has its own page. WJEC AS Physics students sit this topic in the first year.
- Stress, strain and the Young modulusRecall questions on Stress, strain and the Young modulus.Open →
- Stress–strain graphs and the behaviour of materialsRecall questions on Stress–strain graphs and the behaviour of materials.Open →
- Measuring the Young modulus, and material propertiesRecall questions on Measuring the Young modulus and material properties.Open →
- Hooke's law and elastic strain energyRecall questions on Hooke's law and elastic strain energy.Open →
- Crystalline, amorphous and polymeric solidsRecall questions on Crystalline, amorphous and polymeric solids.Open →
- Dislocations, ductile and brittle fractureRecall questions on Dislocations, ductile and brittle fracture.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Numbers
State the formula for calculating strain.
Key term
Explain why a small scratch on the surface of a glass rod so greatly reduces the stress it can withstand.
Key term
Explain how toughened glass resists fracture.
Key term
Define the limit of proportionality on a stress-strain graph.
Key term
What characterises elastic deformation?
Key term
In a Young modulus experiment, how is the original length of the wire measured?
Key term
Describe how data is collected for determining Young modulus experimentally.
Key term
State Hooke's law.
Key term
Write the equation that links force and extension for a spring obeying Hooke's law, and define each symbol with its unit.
Key term
Name the three classes into which solids are grouped in this topic.
Key term
Define a crystalline solid in terms of its atomic arrangement.
Numbers
Calculate the stress when force = 7080 N, cross-sectional area = 0.0096 m².
Key term
What characterises plastic deformation?
Key term
What graph is plotted to determine Young modulus from experimental data?
Key term
Describe how a force–extension graph departs from a straight line beyond the limit of proportionality.
Key term
Give two examples of crystalline solids.
Key term
What is a dislocation in a crystalline metal?
Take Solids Under Stress further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Tensile stress vs Tensile strain
Tensile stress: the force per unit area tending to stretch a material. Tensile strain: the extension divided by the original length, which has no units.
The elastic limit vs The limit of proportionality
The elastic limit: the point beyond which a material does not return to its original length. The limit of proportionality: the point beyond which extension is no longer proportional to load.
Questions from this topic
Each one with the model answer underneath.
- 1
State the formula used to calculate stress in a material.
Model answer
σ = F/A, where σ is stress, F is the applied force, and A is the cross-sectional area.
- 2
Calculate the stress when force = 7080 N, cross-sectional area = 0.0096 m².
Model answer
Stress = 7080 ÷ 0.0096 = 7.4 × 10⁵ Pa.
- 3
What is the SI unit of stress?
Model answer
The pascal (Pa).
- 4
Express the pascal in terms of base SI units.
Model answer
1 Pa = 1 N m⁻² = 1 kg m⁻¹ s⁻².
- 5
How is strain defined for a material under tension?
Model answer
Strain is the extension per unit original length of the material.
- 6
State the formula for calculating strain.
Model answer
ε = ΔL/L, where ε is strain, ΔL is the extension, and L is the original length.
What is inside Levo
Six ways to work the same material.
Solids Under Stress revision questions
- Is Solids Under Stress examined at AS in WJEC Physics?
- Yes. It sits in AS Unit 1, which you take in the first year, so it is on the AS paper as well as counting towards the full A level.
- What does Solids Under Stress cover in WJEC AS-Level Physics?
- 6 subtopics: stress, strain and the young modulus, stress–strain graphs and the behaviour of materials, measuring the young modulus, and material properties, hooke's law and elastic strain energy, crystalline, amorphous and polymeric solids and dislocations, ductile and brittle fracture. Each one has its own page with questions and model answers.
- How is Solids Under Stress organised?
- By the WJEC 1420QS specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Solids Under Stress, 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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