Key term
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
Circular Motion
- 2 subtopics
- 8 things to know
- Papers 1, 2 and 3
What Circular Motion covers
Motion in a circle: measuring angle in radians, angular velocity, and why a body moving at constant speed round a circle is nonetheless accelerating.
Where it is assessed
Papers 1, 2 and 3
Newtonian world, astrophysics and particles, drawn on across the papers.
Check the OCR specification ↗The 2 subtopics
Each one has its own page.
- Radians, angular velocity and periodRecall questions on the radian, the period and frequency of circular motion, angular velocity and its relationships to period, frequency and linear speed, with calculations.Open →
- Centripetal force and accelerationRecall questions on why a perpendicular force causes circular motion, centripetal acceleration and centripetal force in terms of speed and angular velocity with calculations, and the whirling bung experiment.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Process
Why does an object moving at constant speed in a circle still accelerate?
Key term
How is the radian defined as a unit of angle?
Numbers
Give the formula for centripetal acceleration in terms of linear speed v and radius r.
Key term
What is the period T of an object in circular motion?
Key term
Why does a constant net force acting perpendicular to an object's velocity cause circular motion?
Key term
Define the frequency f for an object moving in a circle.
Key term
For an object moving in a circle at constant speed, what remains constant and what continuously changes?
Take Circular Motion further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Angular speed vs Linear speed
Angular speed: angle swept per unit time. Linear speed: distance travelled per unit time.
Centripetal force vs Centrifugal force
Centripetal force: resultant inward force producing circular motion. Centrifugal force: apparent outward effect in a rotating frame.
Geostationary orbit vs Polar orbit
Geostationary orbit: equatorial orbit matching Earth’s rotation. Polar orbit: orbit passing over or near both poles.
Questions from this topic
Each one with the model answer underneath.
- 1
How is the radian defined as a unit of angle?
Model answer
The radian is the angle subtended at the centre of a circle by an arc equal in length to the radius.
- 2
How many radians are there in one complete revolution?
Model answer
2π radians.
- 3
What is the period T of an object in circular motion?
Model answer
The time taken for one complete revolution.
- 4
Define the frequency f for an object moving in a circle.
Model answer
The number of complete revolutions per unit time.
- 5
State the equation that relates period T and frequency f.
Model answer
T = 1/f
- 6
Calculate the period when frequency = 24.8 Hz.
Model answer
Period = 1 ÷ 24.8 = 0.0403 s.
What is inside Levo
Six ways to work the same material.
Circular Motion revision questions
- What does Circular Motion cover in OCR A-Level Physics A?
- 2 subtopics: radians, angular velocity and period and centripetal force and acceleration. Each one has its own page with questions and model answers.
- How is Circular Motion organised?
- By the OCR H556 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Circular Motion, 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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