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
Electric and Magnetic Fields
- 19 subtopics
- 33 things to know
- Papers 1 and 3
What Electric and Magnetic Fields covers
Paper 1 content covering electric fields from Coulomb's law to equipotentials, capacitance and exponential discharge, magnetic flux density and the forces on currents and moving charges, electromagnetic induction, and alternating current.
Where it is assessed
Papers 1 and 3
Advanced Physics I, then the general and practical principles paper.
Check the Pearson Edexcel specification ↗The 19 subtopics
Each one has its own page.
- Electric fields and electric field strengthRecall questions on what a field is, the definition E = F/Q and its unit, why N C⁻¹ and V m⁻¹ are the same, and why the test charge must be small.Open →
- Field strength calculations and field diagramsRecall questions on finding force from field strength, whether the field depends on the charge placed in it, uniform fields, and how strength is shown by field-line spacing.Open →
- Coulomb's law and the field of a point chargeRecall questions on Coulomb's law, ε₀ and 1/(4πε₀), how the sign shows attraction or repulsion, and the radial field of a point charge.Open →
- Inverse-square behaviour and combining fieldsRecall questions on how force and field strength change with separation, the log-log test for an inverse-square law, and finding a resultant field from two charges.Open →
- Electric potential and field strength as a potential gradientRecall questions on the definition and unit of potential, field strength as minus the potential gradient, and reading each from the other's graph.Open →
- Uniform fields between parallel plates, and the potential near a point chargeRecall questions on E = V/d, the field between charged plates and where it stops being uniform, and the potential a distance r from a point charge.Open →
- Equipotentials, field diagrams and work doneRecall questions on what an equipotential is, the angle it makes with field lines, why field lines never cross, and the work done moving a charge through a potential difference.Open →
- Capacitance and the energy stored in a capacitorRecall questions on the definition of capacitance and the farad, why Q/V is constant, and the three expressions for the energy stored.Open →
- Capacitor charge and energy calculationsRecall questions on finding charge and energy for a given capacitor and potential difference, the effect of doubling the potential difference, and why the supply delivers more than is stored.Open →
- Charging and discharging graphs and the time constantRecall questions on the shapes of the charge, current and potential difference graphs, why the charging current falls, and the meaning of the time constant.Open →
- The exponential decay equations and logarithmic graphsRecall questions on the decay equations for charge, current and potential difference, and the linear form obtained by taking natural logarithms.Open →
- Investigating capacitor discharge and time-constant calculationsRecall questions on recording a discharge, why a large resistance and a high-resistance voltmeter are needed, and finding the time constant and half-time.Open →
- Magnetic flux density, flux and flux linkageRecall questions on flux density and its unit, magnetic flux and flux linkage, and how field strength is shown on a field-line diagram.Open →
- Forces on currents and moving chargesRecall questions on F = BIl sinθ and F = BQv, Fleming's left-hand rule, why a magnetic field does no work, and why a charge entering at right angles follows a circle.Open →
- The conditions for inducing an e.m.f.Recall questions on what must change for an e.m.f. to be induced, the three factors that set its size, why a steady current induces nothing, and the effect of an iron core.Open →
- Faraday's law and Lenz's lawRecall questions on the two laws and the single equation expressing both, what the minus sign means, how Lenz's law follows from energy conservation, and the magnet-in-a-copper-tube effect.Open →
- Flux linkage graphs and induced e.m.f. calculationsRecall questions on the gradient of a flux linkage against time graph, why its unit is the volt, electromagnetic braking, and calculating an induced e.m.f.Open →
- Alternating current, peak and r.m.s. valuesRecall questions on frequency and period of an alternating supply, peak and peak-to-peak values, the r.m.s. definition, and why mains supplies are quoted as r.m.s.Open →
- Oscilloscope traces and alternating current calculationsRecall questions on reading period and peak potential difference from a trace, converting between peak and r.m.s., and the mean power dissipated in a resistor.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Numbers
In what way is the definition E = F/Q analogous to the definition of gravitational field strength?
Numbers
How is field strength shown on a field-line diagram, does the field at a point depend on the charge placed there, and what happens to the force on a fixed charge if the field strength doubles?
Numbers
What is the equation for the force between two point charges, and what are ε₀ and the combination 1/(4πε₀)?
Numbers
How does the sign of the calculated force show attraction or repulsion, and what is the field strength due to a point charge?
Numbers
What gradient is expected from a log E against log r graph, and what happens if two charges and their separation are all doubled?
Numbers
What is one similarity and one difference between Coulomb's law and Newton's law of gravitation?
Numbers
What is the unit of electric potential, how is field strength related to potential, and why is there a minus sign?
Numbers
How is field strength found from a potential-distance graph, what does the area under a field strength-distance graph represent, and what is the field strength between two parallel charged plates?
Numbers
What is the potential a distance r from a point charge, how does it vary with distance, and what happens to the field strength between parallel plates if their separation is halved at constant potential difference?
Numbers
How do field strength and potential differ with distance, what work is done moving a charge, and why can field lines never cross?
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How are capacitance and the farad defined, and why are practical capacitors rated in microfarads or smaller?
Numbers
Why is the ratio Q/V constant for a capacitor, what happens to the charge if the potential difference falls to a third, and what do the gradients of V-Q and Q-V graphs give?
Process
How much energy is stored by a 470 μF capacitor charged to 12 V?
Process
How much energy is stored by a 2200 μF capacitor charged to 9.0 V?
Process
A 100 μF capacitor holds a charge of 6.0 mC. How much energy is stored?
Numbers
What percentage of the final charge is reached after one time constant, and what happens to the time constant if the resistance is doubled?
Numbers
What is the equation for the charge remaining on a discharging capacitor, and what linear form does taking logarithms give?
Numbers
Which graph gives a straight line from discharge data, how is the time constant found from it, and why is zero never reached?
Key term
Two identical capacitors discharge through different resistors. Which discharges more quickly and why?
Numbers
What are the units of magnetic flux density and magnetic flux, and how is field strength shown on a field-line diagram?
Key term
How is Fleming's left-hand rule applied to an electron, and what provides the centripetal force on a charge circling in a magnetic field?
Process
What happens to the direction of the force on a current-carrying wire in a magnetic field if the current is reversed?
Process
What condition is necessary for an e.m.f. to be induced in a coil?
Process
Why is no e.m.f. induced while a magnet is held stationary inside a coil?
Process
Why does adding a soft iron core increase the e.m.f. induced in a linked coil?
Numbers
Which single equation expresses both Faraday's law and Lenz's law, and what does Lenz's law state?
Numbers
What does the gradient of a flux linkage against time graph give, and what happens to the kinetic energy lost in electromagnetic braking?
Numbers
What does the minus sign in E = −d(Nφ)/dt represent, how does Lenz's law follow from conservation of energy, and which pole is induced when a north pole is pushed towards a coil?
Key term
An e.m.f. is induced in a coil whose circuit is not complete. Why does no current flow?
Numbers
Why is the r.m.s. value of a sinusoidal current smaller than its peak, and why is the average over a cycle useless?
Numbers
Why are mains supplies quoted using r.m.s. rather than peak values?
Numbers
How does the mean power dissipated by an alternating supply in a resistor compare with the peak power?
Take Electric and Magnetic Fields further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Electric field strength vs Electric potential
Electric field strength: force per unit positive charge. Electric potential: work per unit positive charge from infinity.
Magnetic flux vs Magnetic flux linkage
Magnetic flux: field passing through an area. Magnetic flux linkage: flux multiplied by linked turns.
Motor effect vs Generator effect
Motor effect: force on a current in a magnetic field. Generator effect: induced potential from changing flux linkage.
Questions from this topic
Each one with the model answer underneath.
- 1
What is an electric field?
Model answer
It is a region of space in which a charged particle experiences a force.
- 2
Why is an electric field classed as a force field?
Model answer
Because it exerts a force at a distance on any object carrying the relevant property, which for an electric field is charge.
- 3
What property must an object have before an electric field can act on it?
Model answer
It must carry a net electric charge.
- 4
How is electric field strength defined?
Model answer
It is the force per unit positive charge acting on a small charge placed at that point in the field.
- 5
State the defining equation for electric field strength:
Model answer
E = F/Q, where F is the force acting on a charge Q placed at that point.
- 6
What is the SI unit of electric field strength?
Model answer
The newton per coulomb, N C⁻¹, which is equivalent to the volt per metre, V m⁻¹.
What is inside Levo
Six ways to work the same material.
Electric and Magnetic Fields revision questions
- What does Electric and Magnetic Fields cover in Edexcel A-Level Physics?
- 19 subtopics: electric fields and electric field strength, field strength calculations and field diagrams, coulomb's law and the field of a point charge, inverse-square behaviour and combining fields, electric potential and field strength as a potential gradient, uniform fields between parallel plates, and the potential near a point charge, equipotentials, field diagrams and work done, capacitance and the energy stored in a capacitor, capacitor charge and energy calculations, charging and discharging graphs and the time constant, the exponential decay equations and logarithmic graphs, investigating capacitor discharge and time-constant calculations, magnetic flux density, flux and flux linkage, forces on currents and moving charges, the conditions for inducing an e.m.f., faraday's law and lenz's law, flux linkage graphs and induced e.m.f. calculations, alternating current, peak and r.m.s. values and oscilloscope traces and alternating current calculations. Each one has its own page with questions and model answers.
- How is Electric and Magnetic Fields organised?
- By the Edexcel 9PH0 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Electric and Magnetic Fields, on a schedule.
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