Numbers
OCR A-Level Physics A H556
Practical Skills in the Written Papers
The Practical Endorsement
Topic overviewAnalogue and digital measuring instrumentsImproving accuracy with repeat timing, fiducial markers and plumb linesTiming, calipers and micrometersConstructing and testing circuitsSignal generators and oscilloscopesGenerating and measuring wavesData loggers, modelling software and ionising radiation
Physical Quantities and Units
Making Measurements and Analysing Data
Nature of Quantities
Motion
Forces in Action
Work, Energy and Power
Materials
Newton’s Laws of Motion and Momentum
Charge and Current
Energy, Power and Resistance
Electrical Circuits
Waves
Topic overviewProgressive waves and their propertiesThe wave equationReflection, refraction and diffractionWave graphs and intensityThe electromagnetic spectrumPolarisationRefraction and refractive indexCritical angle and total internal reflectionThe principle of superpositionInterference, coherence and path differenceTwo-source interference, Young's double-slit experiment and the diffraction gratingForming stationary wavesStationary waves on strings and in air columnsMeasuring the speed of soundNode spacing, amplitude and phase in stationary wavesHarmonics and the fundamental mode
Quantum Physics
Thermal Physics
Topic overviewThermal equilibrium and absolute temperatureThe kinetic model of solids, liquids and gasesBrownian motion and internal energySpecific heat capacityMeasuring specific heat capacitySpecific latent heatMeasuring specific latent heatMoles, the Avogadro constant and kinetic theoryGas laws, the ideal gas equation and r.m.s. speedMaxwell-Boltzmann distribution, Boltzmann constant and internal energy
Oscillations
Gravitational Fields
Astrophysics and Cosmology
Topic overviewThe solar system and the birth of a starThe death of a low-mass starSupernovae, neutron stars and black holesThe Hertzsprung-Russell diagramEnergy levels and emission spectraAbsorption spectra and spectral linesPhoton energy and the diffraction gratingWien's law and Stefan's lawAstronomical distances, parallax and the cosmological principleDoppler shift and Hubble's lawThe expanding universe and the Big BangEvidence for the Big Bang and dark energy
Capacitors
Topic overviewCapacitance and charging a capacitorCapacitors in seriesCapacitors in parallel and combined circuitsEnergy stored by a capacitorCharging and discharging through a resistorInvestigating capacitor dischargeThe time constantIterative modelling, exponential decay and the constant-ratio property
Electric Fields
Electromagnetism
Nuclear and Particle Physics
Topic overviewAlpha-particle scattering and the nuclear modelProton number, nucleon number and isotopesThe strong nuclear force and nuclear radiusParticles, antiparticles and hadronsLeptons and the quark modelQuark composition and chargesBeta decay in the quark modelRadioactive decay and the three radiationsNuclear decay equationsActivity, decay constant and half-lifeExponential decay and radioactive datingMass-energy equivalenceAnnihilation, mass defect and binding energyBinding energy per nucleon and induced fissionThe fission reactor and nuclear wasteNuclear fusion and balancing nuclear equations
Materials
- 5 subtopics
- 15 things to know
- Papers 1 and 3
What Materials covers
How solids deform: Hooke's law and springs, the energy stored in a stretched material, stress, strain and the Young modulus, and what a stress-strain graph reveals about a material.
Where it is assessed
Papers 1 and 3
Forces and motion, examined on Modelling Physics and Unified Physics.
Check the OCR specification ↗The 5 subtopics
Each one has its own page.
- Hooke's law and springsRecall questions on tensile and compressive deformation, extension and compression, Hooke's law and the force constant, F = kx calculations, force-extension graphs for springs, investigating force-extension characteristics and elastic deformation.Open →
- Force-extension graphs and work doneRecall questions on plotting force-extension graphs, work done from the area under them, E = ½Fx, loading and unloading curves, rubber band behaviour and hysteresis, and a metal wire stretched beyond its elastic limit.Open →
- Elastic potential energy, stress and strainRecall questions on stress and strain with their formulae, units and calculations, elastic potential energy from force and extension or force constant, ultimate tensile strength, the elastic limit and the limit of proportionality.Open →
- The Young modulusRecall questions on defining the Young modulus, its formula, units and calculation, and the experiment to determine it for a wire: measuring length, diameter and extension, why a long thin wire is used, and the graph plotted.Open →
- Stress-strain graphs and material behaviourRecall questions on stress-strain graphs for ductile, brittle and polymeric materials, loading and unloading a polythene strip, and plastic deformation.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
What does each symbol in F = kx represent, how does k relate to stiffness, and what shape is the force-extension graph for a spring obeying Hooke's law?
Numbers
State the formula for elastic potential energy stored in a spring obeying Hooke's law, and define stress and state its formula.
Numbers
State the formula for work done in stretching a material that obeys Hooke's law, explain why it is ½Fx rather than Fx, and state how work done is found from a force-extension graph.
Key term
Why does strain have no units, and what are ultimate tensile strength and the Young modulus?
Key term
What is the SI unit of stress?
Numbers
State the formula for Young modulus and identify each term.
Key term
How is the cross-sectional area of a wire determined when measuring Young modulus?
Key term
What graph should be plotted after collecting force-extension data?
Key term
Describe the key features of a stress-strain graph for a ductile material.
Key term
What characterises a ductile material in terms of its deformation behaviour?
Key term
How can the work done in stretching a spring or wire be determined from a force-extension graph?
Key term
Describe the shape of a force-extension graph for a metal wire as it is stretched beyond its elastic limit.
Key term
Define Young modulus.
Key term
Describe the shape of a stress-strain graph for a brittle material.
Take Materials 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 applied per unit cross-sectional area. Tensile strain: the extension expressed as a fraction of the original length.
Elastic deformation vs Plastic deformation
Elastic deformation: a change of shape that reverses completely when the load is removed. Plastic deformation: a change of shape that remains after the load is removed.
The Young modulus vs The force constant
The Young modulus: the ratio of stress to strain in the region where the material obeys Hooke's law. The force constant: the force needed per unit extension for one particular specimen.
Questions from this topic
Each one with the model answer underneath.
- 1
What type of deformation occurs when forces stretch a material, causing it to extend?
Model answer
Tensile deformation
- 2
What type of deformation occurs when forces squeeze a material, causing it to shorten?
Model answer
Compressive deformation
- 3
Define extension in the context of material deformation.
Model answer
Extension is the increase in length of a material under tensile force
- 4
Define compression in the context of material deformation.
Model answer
Compression is the decrease in length of a material under compressive force
- 5
State Hooke's law.
Model answer
The extension of a spring is directly proportional to the applied force, provided the limit of proportionality is not exceeded
- 6
What is the force constant k of a spring or wire?
Model answer
The force per unit extension
What is inside Levo
Six ways to work the same material.
Materials revision questions
- What does Materials cover in OCR A-Level Physics A?
- 5 subtopics: hooke's law and springs, force-extension graphs and work done, elastic potential energy, stress and strain, the young modulus and stress-strain graphs and material behaviour. Each one has its own page with questions and model answers.
- How is Materials organised?
- By the OCR H556 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Materials, 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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