Key term
Eduqas A-Level Physics A420QS
Basic Physics
Kinematics
Dynamics
Energy Concepts
Circular Motion
Vibrations
Topic overviewDefining simple harmonic motionFrequency, period, amplitude and phaseThe displacement equation for simple harmonic motionVelocity in simple harmonic motionDisplacement and velocity graphsThe mass-spring oscillatorThe simple pendulumEnergy in simple harmonic motionFree oscillation and dampingForced oscillation and resonance
Kinetic Theory
Thermal Physics
Conduction of Electricity
Resistance
Topic overviewPotential difference and the voltResistance, Ohm's law and the ohmI–V characteristics of a metal wire and a filament lampElectrical power and energy transferThe microscopic origin of resistanceResistivity and the equation R = ρl/AResistance and temperatureSuperconductivity and the transition temperatureHigh temperature superconductors and their uses
D.C. Circuits
Capacitance
Solids Under Stress
Electrostatic and Gravitational Fields of Force
Topic overviewElectric field strength and Coulomb's lawGravitational field strength and Newton's law of gravitationField lines and equipotential surfacesElectric potential and potential energyGravitational potential and potential energyResultant fields and potentials from several sourcesComparing electric and gravitational fields
Using Radiation to Investigate Stars
Orbits and the Wider Universe
Topic overviewKepler's laws of planetary motionNewton's law of gravitation applied to planets and satellitesDeriving Kepler's third law for a circular orbitUsing orbital data to find the mass of the central objectGalactic rotation curves and dark matterThe centre of mass of a two-body systemThe Doppler shift of spectral lines and radial velocityMasses in a double system from radial velocity dataHubble's law, the age of the universe and its fate
The Nature of Waves
Wave Properties
Topic overviewDiffraction at slits and obstaclesWavelength, slit width and the spread of the beamThe principle of superpositionCoherence and the conditions for interferencePath difference and the interference conditionsYoung's double slit experimentThe historical importance of Young's experimentThe diffraction gratingComparing the grating with the double slitStationary waves
Refraction of Light
Photons
Topic overviewPhotons and the quantum of lightDemonstrating the photoelectric effectThe vacuum photocell and stopping potentialEinstein's equation and the energy graphThe electromagnetic spectrum and photon energiesLine emission and line absorption spectraAtomic energy levelsIonisation energy from an energy level diagramElectron diffraction and the de Broglie relationship
Lasers
Nuclear Decay
Topic overviewSpontaneous decay and the nature of α, β and γ radiationNuclear transformation equations and nuclide notationDistinguishing α, β and γ by ionisation, penetration and rangeBackground radiation and gamma intensity with distanceActivity, the becquerel and the decay constantThe exponential decay law and half-life
Particles and Nuclear Structure
Topic overviewThe Rutherford alpha particle scattering experimentCoulomb repulsion in the plum pudding and Rutherford modelsQuarks and leptons: the first generationAntiparticles, annihilation and their symbolsHadrons: baryons, antibaryons and mesonsQuark composition of the proton, neutron and pionsThe four fundamental interactionsConservation laws in particle reactions
Nuclear Energy
Magnetic Fields
Topic overviewThe motor effect and Fleming's left-hand ruleF = BIl sinθ and measuring magnetic flux densityThe force on a moving charge, F = Bqv sinθThe Hall effect and the Hall probeMagnetic fields due to a straight wire and a solenoidForces between current-carrying conductorsCharged particle beams and accelerators
Electromagnetic Induction
Option A: Alternating CurrentsOption A
Topic overviewElectromagnetic induction in a rotating coilFrequency, period, peak and rms valuesMean power dissipated in a resistorUsing an oscilloscope to measure voltage and frequencyInductors in a.c. circuits and inductive reactanceCapacitors in a.c. circuits and capacitive reactancePhasors, phase angle and impedanceResonance in the series RCL circuit and the Q factor
Option B: Medical PhysicsOption B
Topic overviewThe nature and properties of X-raysX-ray production and controlling the beamAttenuation of X-rays and half-value thicknessX-ray imaging, fluoroscopy and radiographyComputed tomography scanningUltrasound generation and acoustic impedanceUltrasound scanning and the Doppler techniqueMagnetic resonance and MRIRadiation effects on living matter and dosimetryRadionuclide tracers, the gamma camera and PET
Option C: The Physics of SportsOption C
Topic overviewCentre of gravity, stability and topplingMoments in muscle systems and other sporting contextsImpulse and Newton's second law in sportThe coefficient of restitutionMoment of inertiaAngular acceleration, torque and angular momentumConservation of angular momentum and rotational energyProjectiles, Bernoulli's equation and drag
Option D: Energy and the EnvironmentOption D
Mathematical Requirements (Appendix C)
Topic overviewUnits, prefixes and standard formSignificant figures and arithmetic meansUncertainty and how uncertainties combineRatios, proportionality and order of magnitude estimatesRearranging and solving physics equationsLogarithms, exponentials and decayResolving vectors, Pythagoras and trigonometryRadians, small angles, areas and volumesStraight-line graphs, gradients and interceptsTangents, areas under curves and logarithmic plots
Photons
- 9 subtopics
- 27 things to know
- Component 3
What Photons covers
Photons is examined in Component 3, Light, Nuclei and Options, Section A, which every student sits. It covers photons and the quantum of light, Demonstrating the photoelectric effect, the vacuum photocell and stopping potential, Einstein's equation and the energy graph, the electromagnetic spectrum and photon energies, line emission and line absorption spectra, atomic energy levels, ionisation energy from an energy level diagram and electron diffraction and the de Broglie relationship.
Where it is assessed
Component 3
Light, Nuclei and Options, Section A, the compulsory core.
Check the Eduqas specification ↗The 9 subtopics
Each one has its own page.
- Photons and the quantum of lightRecall questions on what a photon is, E = hf and its wavelength form with the Planck constant, the electronvolt and conversions to joules, worked photon energy calculations, comparing red with violet, and the number of photons a laser emits each second.Open →
- Demonstrating the photoelectric effectPhotoelectric effect, observed if the electroscope is charged positively instead and threshold frequency.Open →
- The vacuum photocell and stopping potentialConstruction of a vacuum photocell and stopping potential.Open →
- Einstein's equation and the energy graphWork function of a metal, einstein's photoelectric equation and define every symbol and einstein's equation in words.Open →
- The electromagnetic spectrum and photon energiesRecall questions on the range of the visible spectrum and the order of magnitude of the wavelength of each other region, what all the regions have in common, typical photon energies, and why the short-wavelength regions are ionising and the long ones are not.Open →
- Line emission and line absorption spectraAppearance of a line emission spectrum, appearance of a line absorption spectrum and how the spectrum appears when viewed through a diffraction grating.Open →
- Atomic energy levelsEnergy level in an atom, ground state and excited state.Open →
- Ionisation energy from an energy level diagramIonisation energy of an atom and convergence limit of a line spectrum.Open →
- Electron diffraction and the de Broglie relationshipRecall questions on the electron diffraction tube and why rings rather than spots appear, p = h/λ and its application to matter and to photons, worked wavelengths for an electron and for an everyday object, and why the wave nature of large bodies is never seen.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
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What is the photoelectric effect, what happens if the electroscope is charged positively, and why must the plate be cleaned?
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Why must the photocell be evacuated?
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Define the work function of a metal.
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List the regions of the electromagnetic spectrum in order of increasing wavelength.
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How is a line emission spectrum produced?
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What is meant by an energy level in an atom?
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An atom has a ground state at −13.6 eV. State its ionisation energy.
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Describe the electron diffraction demonstration.
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What is a photon?
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What is the photoelectric effect?
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How is the maximum kinetic energy of the emitted electrons measured with a photocell?
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Explain Einstein's equation in words.
Numbers
Calculate the typical photon energy of visible light of wavelength 500 nm, in electronvolts.
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Describe the appearance of a line emission spectrum.
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Why are the energy levels of an atom given negative values?
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Convert an ionisation energy of 13.6 eV into joules
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Why does a ring pattern appear rather than separate spots?
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State the value of the Planck constant.
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Describe how the photoelectric effect can be demonstrated with a gold leaf electroscope.
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Define the stopping potential.
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Give the relationship between the work function and the threshold frequency.
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Give the order of magnitude of the photon energy of an X-ray of wavelength 10⁻¹⁰ m.
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How is a line absorption spectrum produced?
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What is the ground state?
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What is the ionisation energy measured from if the electron is already in an excited state?
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Give the de Broglie relationship and define every symbol.
Take Photons further
The same content, four other ways.
Questions from this topic
Each one with the model answer underneath.
- 1
What is a photon?
Model answer
A photon is a discrete packet, or quantum, of electromagnetic energy.
- 2
Give the equation for the energy of a photon and define every symbol with its unit.
Model answer
E = hf, where E is the photon energy in joules, h the Planck constant in J s and f the frequency in hertz.
- 3
State the value of the Planck constant.
Model answer
6.63 × 10⁻³⁴ J s.
- 4
Write the photon energy equation in terms of wavelength.
Model answer
E = hc/λ, where c is the speed of light in m s⁻¹ and λ the wavelength in metres.
- 5
Calculate the energy of a photon of frequency 5.0 × 10¹⁴ Hz.
Model answer
E = hf = 6.63 × 10⁻³⁴ × 5.0 × 10¹⁴, which is 3.3 × 10⁻¹⁹ J.
- 6
Check that energy by working back to the frequency.
Model answer
f = E/h = 3.3 × 10⁻¹⁹ ÷ 6.63 × 10⁻³⁴, which is 5.0 × 10¹⁴ Hz, as given.
What is inside Levo
Six ways to work the same material.
Photons revision questions
- What does Photons cover in Eduqas A-Level Physics?
- 9 subtopics: photons and the quantum of light, demonstrating the photoelectric effect, the vacuum photocell and stopping potential, einstein's equation and the energy graph, the electromagnetic spectrum and photon energies, line emission and line absorption spectra, atomic energy levels, ionisation energy from an energy level diagram and electron diffraction and the de broglie relationship. Each one has its own page with questions and model answers.
- How is Photons organised?
- By the Eduqas A420QS specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Photons, 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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