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 Radiation
- 7 subtopics
- 11 things to know
- Papers 2 and 3
What Nuclear Radiation covers
Paper 2 content covering binding energy and the curve that explains both fission and fusion, the three types of nuclear radiation and how they are absorbed, nuclear equations, and the random, spontaneous nature of radioactive decay.
Where it is assessed
Papers 2 and 3
Advanced Physics II, then the general and practical principles paper.
Check the Pearson Edexcel specification ↗The 7 subtopics
Each one has its own page.
- Mass deficit, binding energy and the atomic mass unitRecall questions on binding energy and mass deficit, why a nucleus is lighter than its nucleons, ΔE = c²Δm, and the atomic mass unit in SI units, joules and MeV.Open →
- Binding energy per nucleon, fission and fusionRecall questions on why binding energy per nucleon measures stability, the shape of the curve and the nuclide at its peak, and why fusion needs high temperature and density.Open →
- Background radiation and the three types of nuclear radiationRecall questions on the sources of background radiation, correcting a count rate for it, and what alpha, beta-minus and gamma radiation are.Open →
- Ionising power, penetration and changes in the nucleusRecall questions on ranges and absorbers, the ranking for ionising ability and the link with penetration, deflection in an electric field, and how each decay changes the nucleus.Open →
- Nuclear equations and investigating gamma absorptionRecall questions on which quantities balance, writing alpha and beta-minus equations, the lead absorption experiment and its graph, and half-value thickness.Open →
- Activity, the decay constant and half-lifeRecall questions on decay being spontaneous and random, the definitions and units of activity and decay constant, and how λ = ln 2 / t½ follows.Open →
- Decay graphs and half-life calculationsRecall questions on the exponential equations and their logarithmic form, which graph gives the decay constant, reading a half-life from a curve, and why heating changes nothing.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Numbers
What is the atomic mass unit in SI units, and how is binding energy per nucleon calculated for helium-4?
Numbers
What is binding energy per nucleon, which nuclide sits at the peak of the curve, and what does fusion require and release?
Evaluation
What are an alpha particle and a beta-minus particle, and why is the background count measured over a long time?
Numbers
Which quantities balance in a nuclear equation, how does gamma emission change a nucleus, and what is the equation for the alpha decay of uranium-238?
Numbers
For carbon-14's beta-minus decay, give the nuclear equation, name what is emitted besides the electron, and say why the source–detector distance must stay constant.
Numbers
How do the nucleon and proton numbers change in alpha decay, and how do alpha, beta and gamma rank for ionising ability?
Numbers
What are the activity of a source and the decay constant, and what are their units?
Numbers
What equation links activity to the decay constant and the number of undecayed nuclei, and what gives the activity after a time t?
Numbers
What is the logarithmic form of the decay equation, and why is a mean of several half-life readings better than one?
Numbers
What fraction of the original nuclei remains after 1.5 half-lives, and what happens to the half-life if the sample is heated strongly?
Take Nuclear Radiation further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Activity vs Count rate
Activity: decays occurring per unit time. Count rate: detected events occurring per unit time.
Half-life vs Decay constant
Half-life: time for activity or undecayed nuclei to halve. Decay constant: probability of decay per nucleus per unit time.
Questions from this topic
Each one with the model answer underneath.
- 1
What is meant by the binding energy of a nucleus?
Model answer
It is the energy that must be supplied to separate a nucleus completely into its individual protons and neutrons.
- 2
What is the mass deficit of a nucleus?
Model answer
It is the difference between the total mass of the separate nucleons and the mass of the assembled nucleus.
- 3
Why is a nucleus always less massive than the nucleons it is made from?
Model answer
Energy is released when the nucleons bind together, and that release of energy corresponds to a loss of mass through ΔE = c²Δm.
- 4
State the equation linking a change in energy to the associated change in mass:
Model answer
ΔE = c²Δm, where c is the speed of light in a vacuum.
- 5
What value of the speed of light should be used in mass–energy calculations?
Model answer
The speed of light in a vacuum is 3.00 × 10⁸ m s⁻¹.
- 6
How is the atomic mass unit defined?
Model answer
One atomic mass unit is one twelfth of the mass of a neutral atom of carbon-12.
What is inside Levo
Six ways to work the same material.
Nuclear Radiation revision questions
- What does Nuclear Radiation cover in Edexcel A-Level Physics?
- 7 subtopics: mass deficit, binding energy and the atomic mass unit, binding energy per nucleon, fission and fusion, background radiation and the three types of nuclear radiation, ionising power, penetration and changes in the nucleus, nuclear equations and investigating gamma absorption, activity, the decay constant and half-life and decay graphs and half-life calculations. Each one has its own page with questions and model answers.
- How is Nuclear Radiation organised?
- By the Edexcel 9PH0 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Nuclear Radiation, 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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