Numbers
Edexcel A-Level Physics 9PH0
Working as a Physicist
Topic overviewSI base units, derived units and homogeneityUnit prefixes, conversion and order-of-magnitude estimatesResolution, random errors and systematic errorsUncertainty and how uncertainties combineImproving measurements, graphs and evaluating resultsPeer review, publication and scientific integrityRisk, benefit and the role of science in society
Mechanics
Topic overviewThe equations of uniformly accelerated motionDisplacement-time and velocity-time graphsScalars and vectorsResolving vectors and finding resultantsProjectile motionFree-body diagrams and Newton's first and second lawsNewton's third law, mass and weightTerminal velocity and measuring g by free fallLinear momentum and its conservationElastic and inelastic collisions in one dimensionThe moment of a forceCentre of gravity, equilibrium and the principle of momentsWork done by a forceKinetic and gravitational potential energyConservation of energy and dissipationPower, and the equation P = FvEfficiency and wasted energy
Electric Circuits
Topic overviewCurrent, charge and potential differenceResistance, Ohm's law and ohmic behaviourElectrical power and energyKirchhoff's laws: the current and potential difference rulesCombining resistances in series and parallelCircuit calculations, meters and component failureI-V characteristics of conductors, lamps and diodesThermistors, light dependent resistors and resistance changeResistivity and determining it experimentallyCharge carriers, drift velocity and I = nqvAThe potential divider equation and the loading effectSensing circuits with thermistors and light dependent resistorsElectromotive force, internal resistance and lost voltsMeasuring e.m.f. and internal resistance, and cells in combination
Materials
Topic overviewDensity and how it is measuredUpthrust and Archimedes' principleFloating, sinking and upthrust calculationsViscosity, laminar flow and Stokes' lawTerminal velocity of a sphere falling through a liquidMeasuring viscosity by the falling-ball methodHooke's law, stress and strainThe Young modulus and calculations with itDetermining the Young modulus of a wireForce-extension graphs, elastic and plastic deformationStress-strain graphs, ductile and brittle materialsElastic strain energy
Waves and Particle Nature of Light
Topic overviewDescribing a progressive waveThe wave equation and its useLongitudinal and transverse wavesDisplacement-distance and displacement-time graphsMeasuring the speed of sound with an oscilloscopeWavefronts, superposition and phaseCoherence, path difference and phase differenceInterference in practiceStationary waves, nodes and antinodesHarmonics on a stretched stringInvestigating a vibrating string, and air columnsIntensity, the inverse square law and refractive indexRefraction, wave speed and the critical angleTotal internal reflection and measuring refractive indexLenses, ray diagrams and the images they formLens power and the thin lens equationLens calculations and magnificationReflection, transmission and the pulse-echo principlePulse-echo calculations, resolution and ultrasoundPolarisation and diffractionSingle-slit patterns and the diffraction grating equationGrating spectra and measuring wavelengthElectron diffraction and the de Broglie equationde Broglie calculations and wave-particle dualityPhotons and photon energyModels of light and the electronvoltLine spectra and atomic energy levelsThe photoelectric effect and Einstein's equationEvidence for the photon model and photoelectric calculations
Further Mechanics
Topic overviewImpulse and force-time graphsConservation of momentum in two dimensionsInvestigating momentum and analysing collisions on videoElastic and inelastic collisionsKinetic energy, momentum and collision calculationsThe radian, angular displacement and angular velocityAngular velocity, period and frequency of rotationCentripetal accelerationCentripetal force and what provides itVertical loops and centripetal force calculations
Electric and Magnetic Fields
Topic overviewElectric fields and electric field strengthField strength calculations and field diagramsCoulomb's law and the field of a point chargeInverse-square behaviour and combining fieldsElectric potential and field strength as a potential gradientUniform fields between parallel plates, and the potential near a point chargeEquipotentials, field diagrams and work doneCapacitance and the energy stored in a capacitorCapacitor charge and energy calculationsCharging and discharging graphs and the time constantThe exponential decay equations and logarithmic graphsInvestigating capacitor discharge and time-constant calculationsMagnetic flux density, flux and flux linkageForces on currents and moving chargesThe conditions for inducing an e.m.f.Faraday's law and Lenz's lawFlux linkage graphs and induced e.m.f. calculationsAlternating current, peak and r.m.s. valuesOscilloscope traces and alternating current calculations
Nuclear and Particle Physics
Topic overviewNuclide notation, isotopes and the alpha scattering experimentConclusions from alpha scattering and the changing model of the atomThermionic emission and linear acceleratorsThe cyclotron and the radius of a charged particle's pathParticle tracks, conservation laws and why high energies are neededMass-energy equivalence, pair production and annihilationParticle energy units and relativistic lifetimesBaryons, mesons, leptons and quark compositionThe six quarks, antiparticles and fundamental particlesConservation of charge, baryon number and lepton numberQuark changes in beta decay and testing particle equations
Thermodynamics
Topic overviewSpecific heat capacity and specific latent heatMeasuring specific heat capacity and calibrating a thermistorMeasuring specific latent heatInternal energy, temperature and absolute zeroMean kinetic energy and the absolute temperature scaleThe kinetic theory equation and its derivationThe ideal gas equation and molecular kinetic energyBoyle's law and investigating a fixed mass of gasBlack body radiation and Wien's lawThe Stefan-Boltzmann law and stellar calculations
Space
Nuclear Radiation
Topic overviewMass deficit, binding energy and the atomic mass unitBinding energy per nucleon, fission and fusionBackground radiation and the three types of nuclear radiationIonising power, penetration and changes in the nucleusNuclear equations and investigating gamma absorptionActivity, the decay constant and half-lifeDecay graphs and half-life calculations
Gravitational Fields
Oscillations
Topic overviewThe conditions for simple harmonic motionDisplacement, velocity and acceleration in simple harmonic motionThe mass-spring oscillator and the simple pendulumDisplacement, velocity and acceleration graphsReading period, amplitude and speed from oscillation graphsEnergy in an undamped oscillationDamping and where the energy goesFree and forced oscillations and resonanceResonance in practice and determining an unknown mass
Nuclear and Particle Physics
- 11 subtopics
- 22 things to know
- Papers 1 and 3
What Nuclear and Particle Physics covers
Paper 1 content that moves from the alpha scattering evidence for the nucleus to the standard quark-lepton model: how particles are accelerated and detected, mass-energy equivalence and the units particle physicists use, and the conservation laws that decide whether an interaction can happen.
Where it is assessed
Papers 1 and 3
Advanced Physics I, then the general and practical principles paper.
Check the Pearson Edexcel specification ↗The 11 subtopics
Each one has its own page.
- Nuclide notation, isotopes and the alpha scattering experimentRecall questions on nucleon and proton number, isotopes, how a nuclide is written, and the arrangement and conditions of the alpha scattering experiment.Open →
- Conclusions from alpha scattering and the changing model of the atomRecall questions on what each of the three observations showed, the force responsible, why the plum pudding model failed, and estimating an upper limit for nuclear diameter.Open →
- Thermionic emission and linear acceleratorsRecall questions on thermionic emission, the energy gained across an accelerating potential difference, why a magnetic field cannot change speed, and why drift tubes lengthen.Open →
- The cyclotron and the radius of a charged particle's pathRecall questions on how a cyclotron is built, where the particle gains energy, why it spirals outwards, and the derivation and use of r = p/(BQ).Open →
- Particle tracks, conservation laws and why high energies are neededRecall questions on reading momentum and charge from a track, why an uncharged particle leaves none, applying conservation at a vertex, and why high energies are required.Open →
- Mass-energy equivalence, pair production and annihilationRecall questions on ΔE = c²Δm, rest energy, the minimum photon energy for pair production, why it needs a nucleus, and why annihilation makes two photons.Open →
- Particle energy units and relativistic lifetimesRecall questions on the electronvolt, MeV and MeV/c², converting between them and SI units, and why fast muons made high in the atmosphere reach the ground.Open →
- Baryons, mesons, leptons and quark compositionRecall questions on the four classes of particle, what a baryon, meson and lepton are, and the quark compositions of the proton, the neutron and the pions.Open →
- The six quarks, antiparticles and fundamental particlesRecall questions on naming the six quarks, why the photon stands alone, the properties of antiparticles, and why the electron is fundamental while the proton is not.Open →
- Conservation of charge, baryon number and lepton numberRecall questions on the three quantum numbers checked, the values assigned to each class, what a broken rule proves, and the equations for beta decay.Open →
- Quark changes in beta decay and testing particle equationsRecall questions on the quark change behind each beta decay, electron capture and annihilation equations, and deciding whether a proposed interaction is allowed.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Numbers
Which force deflects the alpha particles, what did the back-scattered ones show, and what was the plum pudding model?
Process
What does the history of atomic models illustrate about how scientific models develop?
Numbers
How is the equation r = p/(BQ) derived, and what happens to a particle's radius if the magnetic flux density is doubled?
Numbers
Where in a cyclotron does the particle actually gain energy, and what happens to it inside a dee?
Numbers
What is thermionic emission, and how much kinetic energy does an electron gain across an accelerating potential difference?
Process
Why does a track in a detector often spiral inwards rather than staying a circle?
Process
How is conservation of energy applied to an interaction between particles?
Process
Why does a head-on collision between two beams make more energy available than firing a beam at a stationary target?
Numbers
What is the relationship between a change of mass and a change of energy, what is rest energy, and what happens in pair production?
Numbers
Why do particle physicists prefer MeV and MeV/c² to joules and kilograms?
Numbers
What happens in annihilation, and what is the energy of each photon produced when an electron and a positron annihilate at rest?
Key term
Would an observer travelling alongside a fast muon measure its lifetime as extended?
Key term
What are a meson and a lepton, and what collective name is given to particles built from quarks?
Key term
What are the quark compositions of a proton and a neutron, and what are the charges of the up and down quarks?
Numbers
How do the quark compositions of a proton, a neutron and a positive pion give their charges?
Key term
Name the six quarks of the standard model.
Key term
Why are electrons described as fundamental while protons are not?
Numbers
What is the equation for beta-minus decay of a neutron, and does satisfying every conservation rule guarantee that an interaction happens?
Numbers
What is the equation for beta-plus decay of a proton, and which change at quark level underlies beta-minus decay?
Numbers
Which quark change underlies beta-minus decay, and what are the equations for electron capture and for the annihilation of an electron and a positron?
Numbers
What is wrong with writing neutron decay as n to p plus an electron, and why is energy checked separately from quantum numbers?
Take Nuclear and Particle Physics further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Hadron vs Lepton
Hadron: particle experiencing the strong interaction. Lepton: fundamental particle not experiencing the strong interaction.
Baryon vs Meson
Baryon: hadron made from three quarks. Meson: hadron made from a quark and antiquark.
Antiparticle vs Isotope
Antiparticle: counterpart with equal mass and opposite quantum numbers. Isotope: nucleus with fixed proton count and differing neutron count.
Questions from this topic
Each one with the model answer underneath.
- 1
What is meant by the nucleon number, or mass number, of a nucleus?
Model answer
It is the total number of protons and neutrons in the nucleus, given the symbol A.
- 2
What is meant by the proton number, or atomic number, of a nucleus?
Model answer
It is the number of protons in the nucleus, given the symbol Z, and it determines which element the atom is.
- 3
How is the number of neutrons in a nucleus found from A and Z?
Model answer
The neutron number is the nucleon number minus the proton number, N = A − Z.
- 4
How are the two numbers written when a nuclide is represented in symbol form?
Model answer
The nucleon number is written as a superscript to the left of the chemical symbol and the proton number as a subscript below it.
- 5
What are isotopes, in terms of proton number and nucleon number?
Model answer
Isotopes are nuclei of the same element that have the same proton number but different numbers of neutrons, and therefore different nucleon numbers.
- 6
Why does the proton number, rather than the nucleon number, fix an atom's chemical behaviour?
Model answer
The proton number sets the nuclear charge and hence the number of electrons in the neutral atom, and chemical behaviour depends on those electrons.
What is inside Levo
Six ways to work the same material.
Nuclear and Particle Physics revision questions
- What does Nuclear and Particle Physics cover in Edexcel A-Level Physics?
- 11 subtopics: nuclide notation, isotopes and the alpha scattering experiment, conclusions from alpha scattering and the changing model of the atom, thermionic emission and linear accelerators, the cyclotron and the radius of a charged particle's path, particle tracks, conservation laws and why high energies are needed, mass-energy equivalence, pair production and annihilation, particle energy units and relativistic lifetimes, baryons, mesons, leptons and quark composition, the six quarks, antiparticles and fundamental particles, conservation of charge, baryon number and lepton number and quark changes in beta decay and testing particle equations. Each one has its own page with questions and model answers.
- How is Nuclear and Particle Physics organised?
- By the Edexcel 9PH0 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Nuclear and Particle Physics, 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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