Key term
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
Evaluation
- 3 subtopics
- 9 things to know
- Components 01, 02 and 03
What Evaluation covers
Evaluation 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 drawing conclusions and identifying anomalies, precision, accuracy and margins of error and Limitations and improvements.
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 3 subtopics
Each one has its own page.
- Drawing conclusions and identifying anomaliesRecall questions on spotting and handling an odd reading, telling it from random scatter, when two results agree, uncertainty bars, and limiting a conclusion to the range tested.Open →
- Precision, accuracy and margins of errorRecall questions on precision against accuracy, random and systematic errors, the uncertainty of millimetre scale and digital readings, percentage uncertainty and percentage error, zero errors, margins of error, the period and its uncertainty from many oscillations, quoting uncertainties to one significant figure, calibration, and thermometer uncertainties.Open →
- Limitations and improvementsRecall questions on distinguishing a limitation from a mistake, improving hand timing and small measurements, reducing heat loss and heating effects, data loggers, and why vague suggestions do not count.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Why does a graph reveal anomalies, what should the experimenter do next, and what can cause a single anomalous reading?
Key term
What should be done when a result disagrees with the accepted value by far more than the stated uncertainty?
Key term
Which type of error is reduced by taking repeats and averaging, and which is not?
Evaluation
What is the difference between a limitation of a procedure and a mistake by the experimenter?
Numbers
A length is recorded as 25.0 ± 0.1 cm. Calculate its percentage uncertainty.
Key term
In an experiment to find the specific heat capacity of a metal block, energy is lost to the surroundings. Suggest two improvements.
Numbers
An experiment gives g as 9.6 m s⁻² when the accepted value is 9.81 m s⁻². Calculate the percentage error.
Key term
A wire warms noticeably during a set of resistance measurements. Suggest an improvement.
Take Evaluation further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Precision vs Accuracy
Precision: how closely repeated readings of the same quantity agree with one another. Accuracy: How close a reading lies to the true value of the quantity.
Random error vs Systematic error
Random error: scatter that shifts readings either way by differing amounts, so averaging several of them reduces its effect. Systematic error: A fault that shifts every reading the same way by the same amount, so averaging cannot remove it at all.
Percentage error vs Percentage uncertainty
Percentage error: how far a result lies from the accepted value, expressed as parts per hundred of that accepted value. Percentage uncertainty: The margin either side of a reading within which the true value is expected to lie, expressed as parts per hundred of the reading itself.
Questions from this topic
Each one with the model answer underneath.
- 1
What is an anomalous result?
Model answer
It is a measurement that lies far outside the pattern set by the other results and cannot be accounted for by the normal scatter of the readings.
- 2
How is an anomaly spotted in a table of results?
Model answer
By comparing repeats at the same conditions, since one value very different from the others taken under identical conditions stands out.
- 3
Why does a graph reveal anomalies more readily than a table?
Model answer
The eye follows the trend of a line, so a point well away from the line of best fit is obvious even when the numbers themselves look plausible.
- 4
What should an experimenter do on noticing an anomaly while the apparatus is still set up?
Model answer
Repeat that measurement immediately, checking the apparatus and the conditions, since the cause can rarely be found afterwards.
- 5
Should an anomalous reading simply be deleted from the record?
Model answer
No, it should be recorded and marked, excluded from the mean only if there is a stated reason, and mentioned in the evaluation.
- 6
What can cause a single anomalous reading?
Model answer
A misread or mistyped value, and a momentary change in conditions such as a loose contact, a draught or the apparatus being disturbed.
What is inside Levo
Six ways to work the same material.
Evaluation revision questions
- What does Evaluation cover in OCR A-Level Physics B?
- 3 subtopics: drawing conclusions and identifying anomalies, precision, accuracy and margins of error and limitations and improvements. Each one has its own page with questions and model answers.
- How is Evaluation organised?
- By the OCR H557 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Evaluation, 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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