Lesson 07
Test
Assess the nuclear and quantum physics topic.
Syllabus
CIE 9702 syllabus points
25 linked
- 22.2.1 understand that photoelectrons may be emitted from a metal surface when it is illuminated by electromagnetic radiation
- 22.2.2 understand and use the terms threshold frequency and threshold wavelength
- 22.2.3 explain photoelectric emission in terms of photon energy and work function energy 1
- 22.2.4 recall and use hf = Φ + 2 mvmax2
- 22.2.5 explain why the maximum kinetic energy of photoelectrons is independent of intensity, whereas the photoelectric current is proportional to intensity
- 22.3.1 understand that the photoelectric effect provides evidence for a particulate nature of electromagnetic radiation while phenomena such as interference and diffraction provide evidence for a wave nature
- 22.3.2 describe and interpret qualitatively the evidence provided by electron diffraction for the wave nature of particles
- 22.3.3 understand the de Broglie wavelength as the wavelength associated with a moving particle
- 22.3.4 recall and use λ = h / p
- 22.4.1 understand that there are discrete electron energy levels in isolated atoms (e.g. atomic hydrogen)
- 22.4.2 understand the appearance and formation of emission and absorption line spectra
- 22.4.3 recall and use hf = E1 – E2
- 23.1.1 understand the equivalence between energy and mass as represented by E = mc2 and recall and use this equation
- 23.1.2 represent simple nuclear reactions by nuclear equations of the form 147 N + 24 He " 178 O + 11 H
- 23.1.3 define and use the terms mass defect and binding energy
- 23.1.4 sketch the variation of binding energy per nucleon with nucleon number
- 23.1.5 explain what is meant by nuclear fusion and nuclear fission
- 23.1.6 explain the relevance of binding energy per nucleon to nuclear reactions, including nuclear fusion and nuclear fission
- 23.1.7 calculate the energy released in nuclear reactions using E = c2∆ m
- 23.2.1 understand that fluctuations in count rate provide evidence for the random nature of radioactive decay
- 23.2.2 understand that radioactive decay is both spontaneous and random
- 23.2.3 define activity and decay constant, and recall and use A = λN
- 23.2.4 define half-life
- 23.2.5 use λ = 0.693 / t 1 2
- 23.2.6 understand the exponential nature of radioactive decay, and sketch and use the relationship x = x0e –λt, where x could represent activity, number of undecayed nuclei or received count rate
Definitions
Required definitions
Mass defect
the difference between the mass of a nucleus and the total mass of its separate nucleons.
Binding energy
the energy required to separate a nucleus into its individual nucleons.
Nuclear fusion
the joining of light nuclei to form a heavier nucleus.
Nuclear fission
the splitting of a heavy nucleus into two or more smaller nuclei.
Activity
the rate of decay of nuclei in a radioactive sample.
Decay constant
the probability per unit time that an individual nucleus will decay.
Half-life
the time taken for the number of undecayed nuclei, or the activity, to fall to half its initial value.
Lesson Notes
Student guidance and lesson notes
Overview
This test checks the full A3 nuclear and quantum topic: radioactive decay, binding energy, photoelectric emission, line spectra, and wave-particle duality.
What You Need to Know
- Show working clearly when using decay equations, mass-energy equivalence, photon energy, or de Broglie wavelength.
- Correct measured count rates for background where needed.
- Explain physical evidence in words, especially for the photoelectric effect, line spectra, and electron diffraction.
- Use graphs carefully, including exponential decay, binding energy per nucleon, and energy-level diagrams.
How to Work Through It
- Read each question carefully and identify whether it is testing nuclear physics, photon evidence, spectra, or matter waves.
- Write down known quantities, convert units, and choose the relevant equation.
- Keep explanations tied to evidence, not just named effects.
- Check final answers for units, significant figures, and physical sense.
Check Your Understanding
- Can you explain why radioactive decay is random and spontaneous?
- Can you calculate energy release from a mass defect?
- Can you explain why maximum photoelectron kinetic energy depends on frequency, not intensity?
- Can you use an energy-level diagram or de Broglie equation correctly?
Common Mistakes
- Choosing an equation from keywords without checking the physical situation.
- Losing marks through unit conversion between eV, J, kg, u, or MeV.
- Giving vague quantum explanations that do not mention photons, work function, or evidence.
- Reading graph values inaccurately or ignoring background count rate.
Next Steps
- Use the review lesson to correct mistakes and identify which A3 skills need more practice.
- Keep working visible so feedback can target the exact weak step.