Key term
CCEA A-Level Physics 1210
Physical Quantities, Scalars and Vectors
Moments and Equilibrium
Linear Motion and Dynamics
Newton's Laws of Motion
Linear Momentum and Impulse
Work, Energy and Power
Current, Charge and Potential Difference
Resistance and Resistivity
Topic overviewResistance and Ohm's lawOhmic and non-ohmic behaviourResistors in series and in parallelInvestigating current, voltage and resistance in series and parallel circuitsElectrical power and energy in resistive circuitsResistivity and the equation R = ρl/AMeasuring the resistivity of a metalCurrent–voltage characteristics of a conductor, a lamp and a diodeResistance, temperature and superconductivity
Internal Resistance and Potential Dividers
Topic overviewInternal resistance and terminal potential differenceConsequences of internal resistance for external circuitsMeasuring electromotive force and internal resistanceThe potential divider and variable outputPotential dividers in lighting and heating control circuitsLoaded potential dividers and output voltage calculations
Waves
Refraction
Lenses
Superposition, Interference and Diffraction
Topic overviewSuperposition of wavesStanding waves, nodes and antinodesStanding waves on stretched stringsStanding waves in a pipe closed at one endMeasuring the speed of sound with a resonance tubeConditions for observable interferencePath difference and phase differenceYoung's double slitDiffraction at a single slitThe diffraction grating
Quantum Physics
Wave-Particle Duality
Astronomy
Practical Skills and Data Analysis
Topic overviewChoosing and using measuring instrumentsPrecision, accuracy and recording measurementsUsing the cathode ray oscilloscope to measure voltage and frequencyTables, graphs and presenting resultsLinearising a relationship and using the gradientAbsolute and percentage uncertaintyCombining uncertainties and uncertainty on a graphRandom and systematic error, reliability and refining an experiment
Deformation of Solids
Thermal Physics
Topic overviewBoyle's law, Charles's law and the pressure lawThe ideal gas equation pV = nRTThe Avogadro constant, the mole and pV = NkTInternal energy and the distribution of molecular energyThe kinetic theory equation pV = ⅓Nm⟨c²⟩Average molecular kinetic energy and temperatureAbsolute zero and the kelvin scaleSpecific heat capacity and the electrical method
Uniform Circular Motion
Simple Harmonic Motion
Topic overviewDefining simple harmonic motion and a = −ω²xDisplacement, velocity and acceleration: x = A cos ωtThe simple pendulum and T = 2π√(l/g)The loaded spiral spring and T = 2π√(m/k)SHM graphs and finding velocity from a gradientFree vibrations, forced vibrations and resonanceDamping: light, critical and over-damping
The Nucleus and Radioactive Decay
Topic overviewAlpha-particle scattering and the nuclear atomNuclear radius and nucleon numberThe density of nuclear matterAlpha, beta and gamma radiation: nature, penetration and rangeNuclear equations and changes in nucleon and proton numberThe random and exponential nature of radioactive decayActivity, the decay constant and A = −λNExponential decay calculations with A = A₀e^(−λt)Half-life and measuring it
Nuclear Energy, Fission and Fusion
Gravitational Fields
Electric Fields
Capacitors
Magnetic Fields
Charged Particles and Accelerators
The Nucleus and Radioactive Decay
- 9 subtopics
- 27 things to know
- Unit A2 1
What The Nucleus and Radioactive Decay covers
The Nucleus and Radioactive Decay is examined in Unit A2 1, Deformation of Solids, Thermal Physics, Circular Motion, Oscillations and Atomic and Nuclear Physics, and drawn on again in Unit A2 3. It covers alpha-particle scattering and the nuclear atom, nuclear radius and nucleon number, the density of nuclear matter, alpha, beta and gamma radiation: nature, penetration and range, nuclear equations and changes in nucleon and proton number, the random and exponential nature of radioactive decay, activity, the decay constant and A = −λN, exponential decay calculations with A = A₀e^(−λt) and half-life and measuring it.
Where it is assessed
Unit A2 1
Deformation of Solids, Thermal Physics, Circular Motion, Oscillations and Atomic and Nuclear Physics, and again in Unit A2 3.
Check the CCEA specification ↗The 9 subtopics
Each one has its own page.
- Alpha-particle scattering and the nuclear atomArrangement of the alpha-particle scattering experiment and scintillation in this experiment.Open →
- Nuclear radius and nucleon numberRelationship between nuclear radius and nucleon number and proton number.Open →
- The density of nuclear matterValue of the unified atomic mass unit and two assumptions made in estimating the density of nuclear matter.Open →
- Alpha, beta and gamma radiation: nature, penetration and rangeNature of an alpha particle, nature of a beta-minus particle and nature of gamma radiation.Open →
- Nuclear equations and changes in nucleon and proton numberRecall questions on how the nucleon and proton numbers change in alpha, beta-minus, beta-plus and gamma emission, writing balanced nuclear equations for named decays, checking that both numbers balance on each side, identifying the daughter nuclide from a periodic table, and following a decay chain to a stable end.Open →
- The random and exponential nature of radioactive decaySaying that radioactive decay is a random process, saying that radioactive decay is a spontaneous process and why radioactive decay follows an exponential law.Open →
- Activity, the decay constant and A = −λNActivity of a radioactive source and decay constant.Open →
- Exponential decay calculations with A = A₀e^(−λt)Recall questions on the decay equations for activity and for the number of undecayed nuclei, why both follow the same exponential, worked calculations of activity after a stated time and of the time to reach a stated activity, using half-lives as a shortcut, and taking logarithms to straighten a decay curve.Open →
- Half-life and measuring itRecall questions on the definition of half-life, the relation t½ = ln2/λ and conversions both ways, worked calculations of the fraction remaining after several half-lives, measuring a short half-life from a decay curve, correcting for background count rate, and why the measurement is a statistical one.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
Compare the radius of a helium-4 nucleus with that of a uranium-238 nucleus.
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State the equation used to find the density of nuclear matter and define every symbol.
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How does each of the three radiations behave in a magnetic field?
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Compare the ionising powers of alpha, beta and gamma radiation.
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Why must the total charge be the same on both sides of a nuclear equation?
Numbers
A nucleus of uranium-238 decays through a chain to a nucleus of lead-206. Calculate how many alpha particles are emitted in the chain.
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Why can a temperature rise of several hundred degrees not speed up a radioactive decay?
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State the equation relating the rate of change of the number of undecayed nuclei to the number present, and explain its minus sign.
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Why is the half-life of a nuclide the same wherever on the decay curve it is measured?
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Describe how the half-life of a source of a few minutes' half-life can be measured.
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How is the half-life obtained more reliably from a logarithmic graph of the decay data?
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Describe the arrangement of the alpha-particle scattering experiment.
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State the exponential decay equation for activity and define every symbol.
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Why was the metal foil made extremely thin?
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State the value of the unified atomic mass unit.
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Give experimental evidence that radioactive decay is random.
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Define the activity of a radioactive source.
Numbers
A source of initial activity 800 Bq has a half-life of 6.0 hours. Calculate its activity after 18 hours.
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State the main observation of the alpha-particle scattering experiment and what it shows.
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State the relationship between nuclear radius and nucleon number, and define every symbol.
Numbers
Calculate the volume of an aluminium-27 nucleus, whose radius is 3.6 × 10⁻¹⁵ m.
Key term
State the nature of gamma radiation.
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What changes occur to the nucleon number and the proton number of a nucleus when it emits gamma radiation?
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Why does a large sample of a radioactive nuclide give a smooth decay curve even though each individual decay is random?
Key term
Define the becquerel.
Key term
Why must the decay constant and the time be expressed in matching units in the exponential decay equation?
Take The Nucleus and Radioactive Decay further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
Random vs Spontaneous
Random: the moment of an individual event cannot be predicted. Spontaneous: the event is not triggered by anything outside the nucleus.
Questions from this topic
Each one with the model answer underneath.
- 1
Describe the arrangement of the alpha-particle scattering experiment.
Model answer
A narrow beam of alpha particles from a radioactive source was directed at a very thin gold foil inside an evacuated chamber, and a movable zinc sulfide screen with a microscope was used to count the scintillations produced by scattered alpha particles at different angles.
- 2
Why was the scattering chamber evacuated?
Model answer
Alpha particles are absorbed within a few centimetres of air, so the air had to be removed to allow them to reach the foil and the detector without being stopped or scattered by air molecules.
- 3
Why was the metal foil made extremely thin?
Model answer
A thin foil ensures that most alpha particles pass through after interacting with at most one nucleus, so the deflection observed can be interpreted as a single scattering event.
- 4
Why was gold chosen for the foil?
Model answer
Gold is highly malleable and can be beaten into a foil only a few hundred atoms thick, and its nuclei have a large positive charge which produces measurable deflections.
- 5
State the main observation of the alpha-particle scattering experiment and what it shows.
Model answer
The great majority of alpha particles passed straight through the foil with little or no deflection, showing that the atom is mostly empty space.
- 6
About one alpha particle in eight thousand was turned back towards the source. What does this show about the atom?
Model answer
It shows that the positive charge and almost all of the mass of the atom are concentrated in a very small, dense region at the centre, which is the nucleus.
What is inside Levo
Six ways to work the same material.
The Nucleus and Radioactive Decay revision questions
- What does The Nucleus and Radioactive Decay cover in CCEA A-Level Physics?
- 9 subtopics: alpha-particle scattering and the nuclear atom, nuclear radius and nucleon number, the density of nuclear matter, alpha, beta and gamma radiation: nature, penetration and range, nuclear equations and changes in nucleon and proton number, the random and exponential nature of radioactive decay, activity, the decay constant and a = −λn, exponential decay calculations with a = a₀e^(−λt) and half-life and measuring it. Each one has its own page with questions and model answers.
- How is The Nucleus and Radioactive Decay organised?
- By the CCEA 1210 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in The Nucleus and Radioactive Decay, 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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