Key term
Edexcel GCSE Physics 1PH0
Key Concepts of Physics
Motion and Forces
Topic overviewScalar and vector quantitiesExamples of vectors and scalars, and velocitySpeed, distance, time and distance-time graphsAcceleration and the equation v squared minus u squaredVelocity-time graphs and free fallMeasuring speed in the laboratory, and typical everyday speedsNewton's first law, and investigating force, mass and accelerationNewton's second and third lawsWeight, mass and gravitational field strengthCircular motion and centripetal forceInertial mass and momentumCollisions, and force as the rate of change of momentumReaction time, stopping distance and large decelerationsFactors affecting stopping distance and reaction timeBraking distance, speed and work done
Conservation of Energy
Waves
Topic overviewWhat waves transfer, and the evidence for itFrequency, wavelength, amplitude and periodLongitudinal and transverse wavesThe wave equationMeasuring wave speed, and what happens at a boundaryMeasuring waves, and calculating depth from wave velocityReflection, refraction, transmission and absorption at a boundarySound waves, ultrasound and infrasoundUses of ultrasound and infrasound
Light and the Electromagnetic Spectrum
Topic overviewReflection, refraction and total internal reflectionWhy objects appear colouredLenses, ray diagrams and imagesProperties of electromagnetic wavesInvestigating refraction in glass blocksThe groups of the electromagnetic spectrumThe continuous spectrum, and what our eyes can detectAbsorption, transmission and the velocity of electromagnetic wavesEmitting and absorbing thermal radiationConstant temperature and the temperature of the EarthHow radiation is generated, and why danger rises with frequencyHarmful effects of excessive exposure to radiationUses of electromagnetic radiation
Radioactivity
Topic overviewThe atom and the size of atomsIsotopes, atomic number and mass numberRelative masses and charges of subatomic particlesElectron orbits and energy levelsForming ions, and how the atomic model changedTypes of ionising radiationBackground radiation and detecting radioactivityAlpha, beta and gamma, and their penetrating powerBeta-minus and beta-plus decayEffects of decay on atomic number and mass numberBalancing nuclear equationsActivity and the becquerelHalf-life and the randomness of decayHalf-life calculationsUses of radioactivity, and how danger depends on half-lifeThe dangers of ionising radiationSafety precautions, contamination and irradiationRadiotherapy, medical tracers and PET scannersNuclear power and where nuclear energy comes fromFission of uranium-235 and the chain reactionControlling a reactor and generating electricityNuclear fusion and how it differs from fissionWhy fusion needs extreme conditions
Astronomy
Topic overviewWeight and gravitational field strength on other bodiesThe Solar System and the order of the planetsHow ideas about the Solar System and ways of observing it have changedOrbits of moons, planets, comets and satellitesGravity, orbital speed and stable orbitsThe Steady State and Big Bang theoriesEvidence for an expanding UniverseThe Doppler effect and red-shift in galaxiesThe life cycle of a star like the SunThe life cycle of stars more massive than the Sun
Energy – Forces Doing Work
Topic overviewEnergy stores and energy transfer diagramsChanging a system's energy, and measuring work doneWork done and the energy changes it causesGravitational potential and kinetic energy calculationsDissipation and wasted energyPower as the rate of energy transferThe watt, and calculating efficiency
Forces and Their Effects
Electricity and Circuits
Topic overviewThe atom, and drawing circuit diagramsSeries and parallel circuitsPotential difference and the voltmeterEnergy transferred by moving chargeCurrent, charge and measuring currentResistance and the equation V = IRResistors in series and in parallelDesigning circuits to test componentsInvestigating resistance in circuitsCurrent-potential difference graphs for componentsLight-dependent resistors and thermistorsThe heating effect of an electric currentUses of the heating effect, and the equation E = IVtPower as energy transferred per secondCalculating electrical powerEnergy transfer in domestic devices, and power ratingsDirect and alternating currentAlternating current and the UK mains supplyLive and neutral wires, earthing and fusesFuses in the live wire, mains voltages and electrical dangers
Static Electricity
Magnetism and the Motor Effect
Topic overviewMagnetic poles, permanent and induced magnetsUses of magnetic materialsThe magnetic field around a bar magnetPlotting compasses and the Earth's magnetic fieldThe magnetic effect of an electric currentSolenoids and electromagnetsThe motor effect and Fleming's left-hand ruleThe force on a conductor, and how a motor turns
Electromagnetic Induction
Topic overviewInducing a current by moving a magnetFactors affecting an induced potential differenceAlternators and microphonesHow a transformer worksThe transformer turns-ratio equationThe national grid, and step-up and step-down transformersTransformer power calculationsWhy high-voltage transmission reduces energy loss
Particle Model
Topic overviewKinetic theory and differences in densityCalculating density, and investigating itChanges of state and internal energySpecific heat capacitySpecific latent heat and thermal insulationInvestigating the specific heat capacity of waterGas pressure and the motion of particlesAbsolute zero and the kelvin scaleCompressing gases, and the force a gas exertsPressure and volume of a fixed mass of gas
Forces and Matter
Topic overviewElastic and inelastic distortionSpring constant, and linear and non-linear behaviourWork done in stretching a springAtmospheric pressure and pressure in a fluidForce, area and pressureCalculating pressure, and how pressure varies with depthPressure in liquids: density and depthUpthrust, floating and sinking
Electromagnetic Induction
Alternators and microphones
- 3 things to know
- Paper 2
Overview
How alternators and dynamos produce alternating and direct current with slip rings or a commutator, their outputs over one rotation, increasing a generator's output, and how microphones, loudspeakers and headphones convert between sound and electrical signals.
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Name the parts that connect the rotating coil of an alternator to the external circuit.
Key term
Describe how a dynamo produces a current that always flows in the same direction.
Questions from this subtopic
Each one with the model answer underneath.
- 1
Describe how an alternator produces a current that alternates in direction.
Model answer
A coil rotates in a magnetic field and slip rings keep the same coil end joined to the same contact, so the induced current reverses every half turn.
- 2
Name the parts that connect the rotating coil of an alternator to the external circuit.
Model answer
Slip rings and brushes.
- 3
Describe how a dynamo produces a current that always flows in the same direction.
Model answer
A split-ring commutator swaps the coil's connections every half turn, so the current in the external circuit never reverses.
- 4
State the main difference in construction between an alternator and a dynamo.
Model answer
An alternator uses slip rings, while a dynamo uses a split-ring commutator.
- 5
Describe how the output of an alternator changes during one complete rotation of its coil.
Model answer
It rises to a peak, falls to zero, rises to a peak in the opposite direction, and returns to zero.
- 6
Describe how the output of a dynamo changes during one complete rotation of its coil.
Model answer
It rises to a peak and falls to zero twice, but it never reverses direction.
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