Quantum physics — AS & A Level Physics (9702) questions by topic
Quantum physics questions define the de Broglie wavelength, a photon, and wave-particle duality, and name the phenomenon of electron emission from illuminated magnesium, weighted from 8 to 13 marks in this A Level Physics set.
State, explain and deduce dominate the command words, with calculate and draw also common: explain why an electron diffraction pattern changes, rather than just describing it. 15 real questions from 2023 to 2025 papers are gathered here. Submitting answers for instant marking flags a missing 'moving' in a definition or an incorrectly stated formula immediately, instead of after several similar definitions are attempted.
What examiners look for
- A recurring criticism is the word 'moving' frequently missing from definitions involving electrons.
- Examiners note some candidates state an incorrect formula where none is appropriate, or wrongly refer to the photoelectric effect or X-ray production instead of electron diffraction.
- A common mistake is forgetting the central dark circle that is always present regardless of electron speed.
- Reports flag candidates crediting themselves for stating electrons behave as waves without going on to explain the resulting pattern.
- Strong answers link an increase in accelerating potential difference to greater electron momentum and hence a shorter de Broglie wavelength.
May–June 2025, Paper 41
State what is meant by the de Broglie wavelength of a particle.
Answer this question and get it marked →May–June 2025, Paper 42
State what is meant by the photoelectric effect.
Answer this question and get it marked →May–June 2025, Paper 43
State what is meant by the de Broglie wavelength.
Answer this question and get it marked →May–June 2025, Paper 44
Describe what is meant by wave–particle duality.
Answer this question and get it marked →May–June 2024, Paper 41
May–June 2024, Paper 43
October–November 2024, Paper 41
A polished sheet of magnesium in a vacuum emits electrons when it is illuminated by ultraviolet radiation. State the name of this phenomenon.
Answer this question and get it marked →October–November 2024, Paper 42
Electrons in a vacuum are accelerated from rest through a potential difference (p.d.) V to form a beam. The electrons each have mass m and charge q. The beam is incident on a…
Answer this question and get it marked →October–November 2024, Paper 43
A polished sheet of magnesium in a vacuum emits electrons when it is illuminated by ultraviolet radiation. State the name of this phenomenon.
Answer this question and get it marked →May–June 2023, Paper 41
State what is meant by the de Broglie wavelength.
Answer this question and get it marked →May–June 2023, Paper 42
Fig. 8.1 shows the lowest four energy levels of an electron in an isolated atom. Fig. 8.2 shows the lines in the emission spectrum of the atom that correspond to the transitions…
Answer this question and get it marked →May–June 2023, Paper 43
State what is meant by the de Broglie wavelength.
Answer this question and get it marked →October–November 2023, Paper 41
Show that the momentum p of a photon of electromagnetic radiation with wavelength lambda is given by p = h / lambda where h is the Planck constant.
Answer this question and get it marked →October–November 2023, Paper 42
October–November 2023, Paper 43
Show that the momentum p of a photon of electromagnetic radiation with wavelength lambda is given by p = h / lambda where h is the Planck constant.
Answer this question and get it marked →Other AS & A Level Physics topics
- Forces, density and pressure (120)
- Waves (89)
- Practical skills (86)
- Superposition (77)
- D.C. circuits (71)
- Work, energy and power (70)
- Deformation of solids (60)
- Physical quantities and units (54)
- Current of electricity (50)
- Particle physics (46)
- Kinematics (45)
- Nuclear physics (37)