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
Thermodynamics
- 10 subtopics
- 16 things to know
- Papers 2 and 3
What Thermodynamics covers
Paper 2 content on heating and gases: specific heat capacity and specific latent heat and how each is measured, internal energy and the absolute temperature scale, the kinetic theory of an ideal gas and its derivation, and black body radiation with Wien's and Stefan-Boltzmann's laws.
Where it is assessed
Papers 2 and 3
Advanced Physics II, then the general and practical principles paper.
Check the Pearson Edexcel specification ↗The 10 subtopics
Each one has its own page.
- Specific heat capacity and specific latent heatRecall questions on both definitions and their units, the two energy equations, why temperature stays constant during a change of state, and why vaporisation takes more energy than fusion.Open →
- Measuring specific heat capacity and calibrating a thermistorRecall questions on the electrical method and why it reads high, reducing heat losses, and calibrating a thermistor in a potential divider as a thermometer.Open →
- Measuring specific latent heatRecall questions on the funnel-and-heater method for ice, why a second control funnel is used, the boiling-liquid method, and reading a heating curve.Open →
- Internal energy, temperature and absolute zeroRecall questions on what internal energy is, the two molecular contributions, what temperature tells you about molecules, and the meaning of absolute zero.Open →
- Mean kinetic energy and the absolute temperature scaleRecall questions on the link between mean kinetic energy and absolute temperature, converting from Celsius, why the absolute scale must be used, and why a gas cools as a liquid evaporates.Open →
- The kinetic theory equation and its derivationRecall questions on pV = ⅓Nm⟨c²⟩ and what each symbol means, the four assumptions of the model, and the steps from one molecule in a cube to the pressure on a wall.Open →
- The ideal gas equation and molecular kinetic energyRecall questions on pV = NkT and the Boltzmann constant, combining it with the kinetic theory equation, and comparing two gases held at the same temperature.Open →
- Boyle's law and investigating a fixed mass of gasRecall questions on the statement of Boyle's law, why pressure must be changed slowly, why a column length can stand in for volume, and which graph confirms the law.Open →
- Black body radiation and Wien's lawRecall questions on what a black body radiator is, the shape of the radiation curve and how it changes with temperature, and Wien's law applied to a star.Open →
- The Stefan-Boltzmann law and stellar calculationsRecall questions on the law and its constant, which area to use for a star, comparing stars of equal radius or equal temperature, and using both laws together.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Numbers
What is the difference between the specific latent heat of fusion and that of vaporisation?
Numbers
How does an NTC thermistor's resistance change with temperature, and what happens when two blocks of different materials are heated identically?
Process
Why are readings taken only after the liquid has been boiling steadily for some time?
Key term
What does temperature tell you about a body's molecules, and why do two bodies at the same temperature not store equal internal energy?
Numbers
What is absolute zero in degrees Celsius, what happens to internal energy as a solid melts, and which stores more, warm bath or boiling cup?
Numbers
How is a pressure against temperature graph used to find absolute zero, and what happens to mean kinetic energy when the absolute temperature doubles?
Process
What happens to the internal energy of a substance that is heated without changing state?
Numbers
What is the kinetic theory equation relating pressure and volume to molecular motion, and what assumptions does the ideal gas model make?
Numbers
How is pressure defined, and how does a molecule bouncing between the faces of a cube give rise to a force?
Numbers
What is the ideal gas equation in terms of the number of molecules, and what is k, its value and its unit?
Numbers
Which graph of the results confirms Boyle's law, and what feature of it shows the law holds?
Process
How does the radiation curve change as the temperature of the black body is increased?
Numbers
What is the Stefan-Boltzmann law, what does L represent and in what unit, and what is σ?
Numbers
What determines the power radiated per unit area of a black body, and how do the luminosities of two stars at the same temperature compare if one has three times the radius of the other?
Numbers
Which area is used in the Stefan-Boltzmann law for a star, how do two stars of equal radius compare if one is twice as hot as the other, and why are the laws applied to stars?
Take Thermodynamics further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Specific heat capacity vs Specific latent heat
Specific heat capacity: energy required per kilogram per kelvin. Specific latent heat: energy required per kilogram for state change.
Internal energy vs Temperature
Internal energy: total microscopic kinetic and potential energy. Temperature: measure linked to mean molecular kinetic energy.
Ideal gas vs Real gas
Ideal gas: model obeying the gas equation under stated assumptions. Real gas: physical gas that can depart from the model.
Questions from this topic
Each one with the model answer underneath.
- 1
What is meant by the specific heat capacity of a substance?
Model answer
It is the energy needed to raise the temperature of 1 kg of the substance by 1 K, without a change of state.
- 2
What is the unit of specific heat capacity?
Model answer
The unit is J kg⁻¹ K⁻¹.
- 3
State the equation for the energy transferred when a substance changes temperature:
Model answer
The equation is ΔE = mcΔθ, where m is mass, c is specific heat capacity and Δθ is the temperature change.
- 4
Why does it not matter whether Δθ is measured in °C or in K?
Model answer
A temperature interval of one degree Celsius is exactly the same size as an interval of one kelvin, so the difference is numerically identical.
- 5
What is meant by the specific latent heat of a substance?
Model answer
It is the energy needed to change the state of 1 kg of the substance without any change in temperature.
- 6
State the equation linking energy transferred to the mass that changes state:
Model answer
The equation is ΔE = LΔm, where L is the specific latent heat and Δm is the mass changing state.
What is inside Levo
Six ways to work the same material.
Thermodynamics revision questions
- What does Thermodynamics cover in Edexcel A-Level Physics?
- 10 subtopics: specific heat capacity and specific latent heat, measuring specific heat capacity and calibrating a thermistor, measuring specific latent heat, internal energy, temperature and absolute zero, mean kinetic energy and the absolute temperature scale, the kinetic theory equation and its derivation, the ideal gas equation and molecular kinetic energy, boyle's law and investigating a fixed mass of gas, black body radiation and wien's law and the stefan-boltzmann law and stellar calculations. Each one has its own page with questions and model answers.
- How is Thermodynamics organised?
- By the Edexcel 9PH0 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Thermodynamics, on a schedule.
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