Process
OCR A-Level Physics B H557
Planning
Implementing
Analysis
Evaluation
Practical Skills
Use of Apparatus and Techniques
Fundamental Data Analysis
Imaging and Signalling
Topic overviewReal images and the curvature of wave-frontsLens power and focal lengthThe thin lens equation and the Cartesian conventionLinear magnificationMeasuring the power and focal length of a converging lensImages as arrays of numbersBits, bytes and the information in an imageEnhancing a digital imageWave-forms, frequency and wave speedSampling and digitising an analogue signalNoise, resolution and digital transmissionPolarisation of electromagnetic waves
Sensing
Topic overviewCurrent and the flow of chargePotential difference, e.m.f. and energy transferResistance, conductance and Ohm's lawSeries and parallel combinationsPower and energy in electric circuitsInternal resistance and e.m.f.Kirchhoff's laws and conservation in circuitsResistivity and conductivityCharge carrier number density in metals, semiconductors and insulatorsCurrent-potential difference characteristics and circuit componentsThe potential dividerSensing circuits and calibration
Mechanical Properties of Materials
Topic overviewElastic and plastic deformation and fractureHooke's law and force-extension graphsElastic strain energyStress, strain and the Young modulusMeasuring the Young modulus and fracture stress of a metalDescribing and comparing materialsMetals, ceramics and polymersDirect evidence for the size and spacing of particles
Waves and Quantum Behaviour
Topic overviewWaves, phase and superpositionStanding waves on stringsStanding waves in air columns and the speed of soundRefraction, refractive index and Snell's lawTwo-slit interferenceDiffraction at a narrow apertureThe diffraction gratingMeasuring the wavelength of lightPhotons and the quantum E = hfEvidence that photons exchange energy in quantaQuantum behaviour: phasors and probability of arrivalElectron diffraction and the de Broglie wavelength
Space, Time and Motion
Topic overviewScalars, vectors and their representationResolving and adding vectorsDescribing motion: displacement, velocity and accelerationMotion graphsThe kinematic equations for constant accelerationProjectiles and motion in two dimensionsMeasuring motion in the laboratoryDetermining the acceleration of free fallNewton's laws of motionTerminal velocity and resistive forcesMomentum and impulseConservation of momentum and collisionsWork, energy and its conservationPower and modelling motion in small time steps
Creating Models
Topic overviewCapacitance and charge storageEnergy stored on a capacitorCapacitor discharge and the exponential modelThe time constant of an RC circuitCharging a capacitorInvestigating capacitor charge and dischargeRadioactive decay as a random processActivity, decay constant and half-lifeDetermining the half-life of an isotopeIterative numerical models of exponential changeExponential curves on linear and logarithmic scalesSimple harmonic motion: the defining relationshipSolutions and graphs of simple harmonic motionModelling oscillations step by stepEnergy in simple harmonic motionPeriod of a mass–spring system and a simple pendulumFree and forced vibrations, damping and resonance
Out Into Space
Topic overviewGravitational and kinetic energy changesMotion in a uniform gravitational fieldGravitational force and the radial fieldGravitational field strengthGravitational potential energy in a radial fieldGravitational potential and equipotentialsGraphs and diagrams of gravitational fieldsAngular velocity and motion in a horizontal circleCircular gravitational orbits
Our Place in the Universe
Matter: Very Simple
Topic overviewEnergy transfer and specific thermal capacityFinding specific thermal capacity by an electrical methodIdeal gases and the gas lawsInvestigating the gas laws and absolute zeroMoles, the Avogadro constant and the Boltzmann constantThe equation of state for an ideal gasImpulse and force–time graphsThe kinetic theory of ideal gasesTemperature, average energy per particle and internal energyRandom walk of molecules in a gas
Matter: Hot or Cold
Electromagnetism
Topic overviewMagnetic flux, B-fields and flux linkageElectromagnetic induction: Faraday's and Lenz's lawsGraphs of current, flux and induced e.m.f.The dynamoThe transformerEddy currents and real transformersForces on current-carrying conductorsMagnetic circuits, permeance and machine designInvestigating induction, flux density and transformers
Charge and Field
Topic overviewThe uniform electric fieldRadial fields and the inverse square lawElectric potential and potential energyField and potential graphsField lines and equipotential surfacesThe electronvolt and accelerating chargesMillikan's experiment and the discreteness of chargeMoving charges in magnetic fieldsComparing electric and gravitational fields
Probing Deep Into Matter
Topic overviewParticle accelerators and high-energy beamsScattering and the nuclear atomPaths of scattered particles and closest approachDiscrete energy levels in atomsElectron standing waves and the confined electronQuarks, hadrons and leptonsConservation laws and nuclear equationsCharged particles in detectors and magnetic fieldsRelativistic energy and the relativistic factor
Ionising Radiation and Risk
Topic overviewThe nature of ionising radiationsEffects on living tissue and radiation safetyAbsorbed dose, effective dose and riskBinding energy and nuclear stabilityThe Nuclear Valley and modes of decayFission, fusion and nuclear powerActivity, half-life and the decay constantInvestigating absorption and half-life
Matter: Hot or Cold
- 4 subtopics
- 12 things to know
- Components 01, 02 and 03
What Matter: Hot or Cold covers
Matter: Hot or Cold is examined in all three written papers — the specification states that Components 01, 02 and 03 each assess content from across all the teaching modules, so nothing is confined to one paper. It covers energy, temperature and the ratio E/kT, the Boltzmann factor and populations of energy states, graphs of the Boltzmann factor and activation processes and the effect of temperature.
Where it is assessed
Components 01, 02 and 03
Every module can be assessed on any of the three papers.
Check the OCR specification ↗The 4 subtopics
Each one has its own page.
- Energy, temperature and the ratio E/kTRecall questions on kT and its size at room temperature, comparing bond, band-gap and escape energies with it, why the ratio has no unit, and what a small ratio implies.Open →
- The Boltzmann factor and populations of energy statesRecall questions on the Boltzmann factor e^(−E/kT) and why it is below one, its value when the step is kT or 10kT, calculating factors and populations, its limits at very high temperature and near absolute zero, why a small temperature rise matters so much, the classical approximation, finding an activation energy from rates, and states of equal energy.Open →
- Graphs of the Boltzmann factorRecall questions on its shape against energy and against temperature, why it never exceeds one, which logarithmic plots straighten the data, their gradients and intercepts, and obtaining an activation energy.Open →
- Activation processes and the effect of temperatureRecall questions on activation energy and why activated processes speed up sharply with temperature, evaporation and evaporative cooling, thermionic emission and hot cathodes, ionisation in stars, semiconductor and metal resistance, viscosity and cold engine oil, melting over a narrow range, and why refrigeration slows food spoiling.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Why plot Boltzmann factors logarithmically, how do two activation energies differ on such a plot, and what does the e⁻¹ point show?
Key term
What energy increase divides the Boltzmann factor by e, how does higher temperature change its curve, which plot straightens it, and why never above one?
Key term
Explain why the viscosity of a liquid falls as it is heated.
Process
Name three processes that have an activation energy and state the energy step involved in each.
Numbers
Calculate kT at room temperature, taking that as 293 K.
Key term
How does the ratio of the numbers of particles in two states depend on the energy difference between them?
Numbers
An energy step of 6.4 × 10⁻²⁰ J exists at 290 K. Calculate E/kT.
Key term
Why is the Boltzmann factor always less than one?
Numbers
A covalent bond has an energy of about 4 eV. How many times kT is this at room temperature?
Numbers
Calculate the Boltzmann factor when E/kT = 10.
Key term
What increase in energy makes the Boltzmann factor fall to 1/e of its value?
Take Matter: Hot or Cold further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Boltzmann factor vs Boltzmann constant
Boltzmann factor: the pure number e^(−E/kT), giving how many particles sit in a state a step E above another compared with the number in the lower one. Boltzmann constant: the fixed quantity k = 1.38 × 10⁻²³ J K⁻¹ that turns an absolute temperature into the typical thermal energy per particle.
Activation energy vs Energy release
Activation energy: the minimum a particle must acquire before a particular change can happen to it at all, a barrier that has to be crossed first. Energy release: the amount a completed change hands out to its surroundings, which says nothing about how hard that change was to start.
Metal on warming vs Semiconductor on warming
Metal on warming: a conductor whose resistance rises, because its fixed number of free electrons simply suffers more scattering. Semiconductor on warming: a material whose resistance falls, because far more electrons are lifted across the band gap and that exponential gain in carriers outweighs the extra scattering.
Questions from this topic
Each one with the model answer underneath.
- 1
What does the quantity kT represent?
Model answer
It is the typical thermal energy available per particle at an absolute temperature T.
- 2
Calculate kT at room temperature, taking that as 293 K.
Model answer
kT = 1.38 × 10⁻²³ × 293 = 4.0 × 10⁻²¹ J.
- 3
Express kT at room temperature in electronvolts.
Model answer
It is about 0.025 eV, roughly one fortieth of an electronvolt.
- 4
Why is the ratio E/kT more informative than the energy E on its own?
Model answer
It says how large an energy step is compared with the thermal energy available, which is what decides whether the step is often taken.
- 5
Does the ratio E/kT carry a unit?
Model answer
No, both E and kT are energies, so the ratio is a pure number.
- 6
An energy step of 6.4 × 10⁻²⁰ J exists at 290 K. Calculate E/kT.
Model answer
kT = 1.38 × 10⁻²³ × 290 = 4.0 × 10⁻²¹ J, so E/kT = 16.
What is inside Levo
Six ways to work the same material.
Matter: Hot or Cold revision questions
- What does Matter: Hot or Cold cover in OCR A-Level Physics B?
- 4 subtopics: energy, temperature and the ratio e/kt, the boltzmann factor and populations of energy states, graphs of the boltzmann factor and activation processes and the effect of temperature. Each one has its own page with questions and model answers.
- How is Matter: Hot or Cold organised?
- By the OCR H557 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Matter: Hot or Cold, 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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