A2 Physics Paper 4 Black Book
Cambridge A Level Physics 9702
Essential Definitions & Repeated
Questions
2016–2025
What This Guide Covers:
¥ All definition questions from 2020–2025
¥ Mark scheme exact wording for each definition
¥ Most repeated calculation question types
¥ Common examiner report insights
¥ Typical mark allocation patterns
¥ Error avoidance strategies
Argha Saha
,Paper 4 Essential Questions & Definitions 1
Contents
How to Use This Guide 6
1 PART A: Essential Definitions (2020–2025) 7
1.1 Topic 12: Motion in a Circle . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.1.1 Q12.1: Define the radian [1] . . . . . . . . . . . . . . . . . . . . . . . 7
1.1.2 Q12.2: Define angular velocity (angular speed) [1] . . . . . . . . . . . 7
1.1.3 Q12.3: Define centripetal acceleration [1] . . . . . . . . . . . . . . . . 7
1.1.4 Q12.4: Define centripetal force [1] . . . . . . . . . . . . . . . . . . . . 8
1.2 Topic 13: Gravitational Fields . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.2.1 Q13.1: Define gravitational field strength [1] . . . . . . . . . . . . . . 8
1.2.2 Q13.2: State Newton’s law of gravitation [2] . . . . . . . . . . . . . . 8
1.2.3 Q13.3: Define gravitational potential at a point [1] . . . . . . . . . . 9
1.2.4 Q13.4: Define gravitational potential energy [1] . . . . . . . . . . . . 9
1.3 Topic 14: Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.3.1 Q14.1: Define thermal equilibrium [1] . . . . . . . . . . . . . . . . . . 9
1.3.2 Q14.2: Define thermodynamic (absolute) temperature [1] . . . . . . . 10
1.3.3 Q14.3: Define specific heat capacity [1] . . . . . . . . . . . . . . . . . 10
1.3.4 Q14.4: Define specific latent heat of fusion [1] . . . . . . . . . . . . . 10
1.3.5 Q14.5: Define specific latent heat of vaporization [1] . . . . . . . . . . 11
1.4 Topic 15: Ideal Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.4.1 Q15.1: Define the mole [1] . . . . . . . . . . . . . . . . . . . . . . . . 11
1.4.2 Q15.2: State the ideal gas equation [1] . . . . . . . . . . . . . . . . . 11
1.4.3 Q15.3: State the assumptions of the kinetic theory of ideal gases [4] . 12
1.4.4 Q15.4: Define absolute zero (temperature) [1] . . . . . . . . . . . . . 12
1.4.5 Q15.5: State the relationship between average kinetic energy and tem-
perature [1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.4.6 Q15.6: State what is meant by an ideal gas [2] . . . . . . . . . . . . . 13
1.4.7 Q15.7: State what is meant by the Avogadro constant [1] . . . . . . . 13
1.4.8 Q15.8: State the relationship between the Avogadro constant NA , the
molar gas constant R and the Boltzmann constant k [1] . . . . . . . . 14
1.5 Topic 16: Thermodynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.5.1 Q16.1: Define internal energy [1] . . . . . . . . . . . . . . . . . . . . 14
1.5.2 Q16.2: State the first law of thermodynamics [1] . . . . . . . . . . . . 14
1.5.3 Q16.3: State what is meant by thermal equilibrium [1] . . . . . . . . 15
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,Paper 4 Essential Questions & Definitions 2
1.6 Topic 17: Oscillations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.6.1 Q17.1: Define simple harmonic motion (SHM) [2] . . . . . . . . . . . 15
1.6.2 Q17.2: Define period of oscillation [1] . . . . . . . . . . . . . . . . . . 15
1.6.3 Q17.3: Define amplitude of oscillation [1] . . . . . . . . . . . . . . . . 16
1.6.4 Q17.4: Define phase difference [1] . . . . . . . . . . . . . . . . . . . . 16
1.6.5 Q17.5: Define natural frequency [1] . . . . . . . . . . . . . . . . . . . 16
1.6.6 Q17.6: Define resonance [1] . . . . . . . . . . . . . . . . . . . . . . . 16
1.6.7 Q17.7: Define damping [1] . . . . . . . . . . . . . . . . . . . . . . . . 17
1.7 Topic 18: Electric Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
1.7.1 Q18.1: Define electric field strength [1] . . . . . . . . . . . . . . . . . 17
1.7.2 Q18.2: Define electric potential at a point [1] . . . . . . . . . . . . . . 17
1.7.3 Q18.3: State Coulomb’s law [2] . . . . . . . . . . . . . . . . . . . . . 18
1.8 Topic 19: Capacitance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
1.8.1 Q19.1: Define capacitance [1] . . . . . . . . . . . . . . . . . . . . . . 18
1.8.2 Q19.2: Define the farad [1] . . . . . . . . . . . . . . . . . . . . . . . . 18
1.8.3 Q19.3: Define the time constant of a capacitor discharge circuit [1] . . 19
1.9 Topic 20: Magnetic Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
1.9.1 Q20.1: Define magnetic flux density [1] . . . . . . . . . . . . . . . . . 19
1.9.2 Q20.2: Define magnetic flux [1] . . . . . . . . . . . . . . . . . . . . . 19
1.9.3 Q20.3: State Faraday’s law of electromagnetic induction [1] . . . . . . 20
1.9.4 Q20.4: State Lenz’s law [1] . . . . . . . . . . . . . . . . . . . . . . . . 20
1.9.5 Q20.5: Define magnetic flux linkage [1] . . . . . . . . . . . . . . . . . 20
1.10 Topic 21: Alternating Currents . . . . . . . . . . . . . . . . . . . . . . . . . 20
1.10.1 Q21.1: Define the root-mean-square (r.m.s.) value of alternating cur-
rent [1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.10.2 Q21.2: Define the peak value of alternating current [1] . . . . . . . . 21
1.10.3 Q21.3: Define rectification [1] . . . . . . . . . . . . . . . . . . . . . . 21
1.11 Topic 22: Quantum Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.11.1 Q22.1: Define the photon [1] . . . . . . . . . . . . . . . . . . . . . . . 22
1.11.2 Q22.2: State the photoelectric effect [2] . . . . . . . . . . . . . . . . . 22
1.11.3 Q22.3: Define work function [1] . . . . . . . . . . . . . . . . . . . . . 22
1.11.4 Q22.4: State Einstein’s photoelectric equation [1] . . . . . . . . . . . 23
1.11.5 Q22.5: Define threshold frequency [1] . . . . . . . . . . . . . . . . . . 23
1.11.6 Q22.6: Define the electronvolt (eV) [1] . . . . . . . . . . . . . . . . . 23
1.11.7 Q22.7: State the de Broglie wavelength equation [1] . . . . . . . . . . 23
Sciencetadium
, Paper 4 Essential Questions & Definitions 3
1.11.8 Q22.8: Explain wave-particle duality [2] . . . . . . . . . . . . . . . . 24
1.11.9 Q22.9: State what is meant by the de Broglie wavelength [1] . . . . . 24
1.12 Topic 23: Nuclear Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
1.12.1 Q23.1: Define the unified atomic mass unit (u) [1] . . . . . . . . . . . 25
1.12.2 Q23.2: Define mass defect [1] . . . . . . . . . . . . . . . . . . . . . . 25
1.12.3 Q23.3: Define binding energy [1] . . . . . . . . . . . . . . . . . . . . . 25
1.12.4 Q23.4: Define binding energy per nucleon [1] . . . . . . . . . . . . . . 26
1.12.5 Q23.5: Define radioactive decay [1] . . . . . . . . . . . . . . . . . . . 26
1.12.6 Q23.6: Define activity (of a radioactive source) [1] . . . . . . . . . . . 26
1.12.7 Q23.7: Define decay constant [1] . . . . . . . . . . . . . . . . . . . . . 27
1.12.8 Q23.8: Define half-life [1] . . . . . . . . . . . . . . . . . . . . . . . . . 27
1.12.9 Q23.9: State what is meant by random (in the context of radioactive
decay) [1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
1.12.10 Q23.10: State what is meant by spontaneous (in the context of ra-
dioactive decay) [1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
1.13 Topic 24: Medical Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
1.13.1 Q24.1: Define specific acoustic impedance [1] . . . . . . . . . . . . . . 28
1.13.2 Q24.2: Define attenuation [1] . . . . . . . . . . . . . . . . . . . . . . 28
1.13.3 Q24.3: Explain what is meant by a tracer [1] . . . . . . . . . . . . . . 29
1.13.4 Q24.4: Explain what is meant by annihilation [1] . . . . . . . . . . . 29
1.14 Topic 25: Astronomy and Cosmology . . . . . . . . . . . . . . . . . . . . . . 29
1.14.1 Q25.1: Define luminosity (of a star) [1] . . . . . . . . . . . . . . . . . 29
1.14.2 Q25.2: Define apparent brightness (intensity) [1] . . . . . . . . . . . . 30
1.14.3 Q25.3: State Hubble’s law [1] . . . . . . . . . . . . . . . . . . . . . . 30
1.14.4 Q25.4: Define redshift [1] . . . . . . . . . . . . . . . . . . . . . . . . . 30
1.14.5 Q25.5: State Wien’s displacement law [1] . . . . . . . . . . . . . . . . 30
1.14.6 Q25.6: State the Stefan-Boltzmann law [1] . . . . . . . . . . . . . . . 31
1.14.7 Q25.7: State what is meant by a standard candle [1] . . . . . . . . . 31
2 PART B: Most Repeated Calculation Questions 32
2.1 Topic 12: Circular Motion Calculations . . . . . . . . . . . . . . . . . . . . . 32
2.1.1 Q1: Angular Frequency and Centripetal Acceleration [2] . . . . . . . 32
2.2 Topic 13: Gravitational Fields Calculations . . . . . . . . . . . . . . . . . . . 33
2.2.1 Q2: Calculating Orbital Radius from Period [3] . . . . . . . . . . . . 33
2.2.2 Q3: Geostationary Satellite Height [3] . . . . . . . . . . . . . . . . . . 34
2.2.3 Q4: Change in Gravitational Potential Energy [3] . . . . . . . . . . . 35
Sciencetadium
Cambridge A Level Physics 9702
Essential Definitions & Repeated
Questions
2016–2025
What This Guide Covers:
¥ All definition questions from 2020–2025
¥ Mark scheme exact wording for each definition
¥ Most repeated calculation question types
¥ Common examiner report insights
¥ Typical mark allocation patterns
¥ Error avoidance strategies
Argha Saha
,Paper 4 Essential Questions & Definitions 1
Contents
How to Use This Guide 6
1 PART A: Essential Definitions (2020–2025) 7
1.1 Topic 12: Motion in a Circle . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.1.1 Q12.1: Define the radian [1] . . . . . . . . . . . . . . . . . . . . . . . 7
1.1.2 Q12.2: Define angular velocity (angular speed) [1] . . . . . . . . . . . 7
1.1.3 Q12.3: Define centripetal acceleration [1] . . . . . . . . . . . . . . . . 7
1.1.4 Q12.4: Define centripetal force [1] . . . . . . . . . . . . . . . . . . . . 8
1.2 Topic 13: Gravitational Fields . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.2.1 Q13.1: Define gravitational field strength [1] . . . . . . . . . . . . . . 8
1.2.2 Q13.2: State Newton’s law of gravitation [2] . . . . . . . . . . . . . . 8
1.2.3 Q13.3: Define gravitational potential at a point [1] . . . . . . . . . . 9
1.2.4 Q13.4: Define gravitational potential energy [1] . . . . . . . . . . . . 9
1.3 Topic 14: Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.3.1 Q14.1: Define thermal equilibrium [1] . . . . . . . . . . . . . . . . . . 9
1.3.2 Q14.2: Define thermodynamic (absolute) temperature [1] . . . . . . . 10
1.3.3 Q14.3: Define specific heat capacity [1] . . . . . . . . . . . . . . . . . 10
1.3.4 Q14.4: Define specific latent heat of fusion [1] . . . . . . . . . . . . . 10
1.3.5 Q14.5: Define specific latent heat of vaporization [1] . . . . . . . . . . 11
1.4 Topic 15: Ideal Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.4.1 Q15.1: Define the mole [1] . . . . . . . . . . . . . . . . . . . . . . . . 11
1.4.2 Q15.2: State the ideal gas equation [1] . . . . . . . . . . . . . . . . . 11
1.4.3 Q15.3: State the assumptions of the kinetic theory of ideal gases [4] . 12
1.4.4 Q15.4: Define absolute zero (temperature) [1] . . . . . . . . . . . . . 12
1.4.5 Q15.5: State the relationship between average kinetic energy and tem-
perature [1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.4.6 Q15.6: State what is meant by an ideal gas [2] . . . . . . . . . . . . . 13
1.4.7 Q15.7: State what is meant by the Avogadro constant [1] . . . . . . . 13
1.4.8 Q15.8: State the relationship between the Avogadro constant NA , the
molar gas constant R and the Boltzmann constant k [1] . . . . . . . . 14
1.5 Topic 16: Thermodynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.5.1 Q16.1: Define internal energy [1] . . . . . . . . . . . . . . . . . . . . 14
1.5.2 Q16.2: State the first law of thermodynamics [1] . . . . . . . . . . . . 14
1.5.3 Q16.3: State what is meant by thermal equilibrium [1] . . . . . . . . 15
Sciencetadium
,Paper 4 Essential Questions & Definitions 2
1.6 Topic 17: Oscillations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.6.1 Q17.1: Define simple harmonic motion (SHM) [2] . . . . . . . . . . . 15
1.6.2 Q17.2: Define period of oscillation [1] . . . . . . . . . . . . . . . . . . 15
1.6.3 Q17.3: Define amplitude of oscillation [1] . . . . . . . . . . . . . . . . 16
1.6.4 Q17.4: Define phase difference [1] . . . . . . . . . . . . . . . . . . . . 16
1.6.5 Q17.5: Define natural frequency [1] . . . . . . . . . . . . . . . . . . . 16
1.6.6 Q17.6: Define resonance [1] . . . . . . . . . . . . . . . . . . . . . . . 16
1.6.7 Q17.7: Define damping [1] . . . . . . . . . . . . . . . . . . . . . . . . 17
1.7 Topic 18: Electric Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
1.7.1 Q18.1: Define electric field strength [1] . . . . . . . . . . . . . . . . . 17
1.7.2 Q18.2: Define electric potential at a point [1] . . . . . . . . . . . . . . 17
1.7.3 Q18.3: State Coulomb’s law [2] . . . . . . . . . . . . . . . . . . . . . 18
1.8 Topic 19: Capacitance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
1.8.1 Q19.1: Define capacitance [1] . . . . . . . . . . . . . . . . . . . . . . 18
1.8.2 Q19.2: Define the farad [1] . . . . . . . . . . . . . . . . . . . . . . . . 18
1.8.3 Q19.3: Define the time constant of a capacitor discharge circuit [1] . . 19
1.9 Topic 20: Magnetic Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
1.9.1 Q20.1: Define magnetic flux density [1] . . . . . . . . . . . . . . . . . 19
1.9.2 Q20.2: Define magnetic flux [1] . . . . . . . . . . . . . . . . . . . . . 19
1.9.3 Q20.3: State Faraday’s law of electromagnetic induction [1] . . . . . . 20
1.9.4 Q20.4: State Lenz’s law [1] . . . . . . . . . . . . . . . . . . . . . . . . 20
1.9.5 Q20.5: Define magnetic flux linkage [1] . . . . . . . . . . . . . . . . . 20
1.10 Topic 21: Alternating Currents . . . . . . . . . . . . . . . . . . . . . . . . . 20
1.10.1 Q21.1: Define the root-mean-square (r.m.s.) value of alternating cur-
rent [1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.10.2 Q21.2: Define the peak value of alternating current [1] . . . . . . . . 21
1.10.3 Q21.3: Define rectification [1] . . . . . . . . . . . . . . . . . . . . . . 21
1.11 Topic 22: Quantum Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.11.1 Q22.1: Define the photon [1] . . . . . . . . . . . . . . . . . . . . . . . 22
1.11.2 Q22.2: State the photoelectric effect [2] . . . . . . . . . . . . . . . . . 22
1.11.3 Q22.3: Define work function [1] . . . . . . . . . . . . . . . . . . . . . 22
1.11.4 Q22.4: State Einstein’s photoelectric equation [1] . . . . . . . . . . . 23
1.11.5 Q22.5: Define threshold frequency [1] . . . . . . . . . . . . . . . . . . 23
1.11.6 Q22.6: Define the electronvolt (eV) [1] . . . . . . . . . . . . . . . . . 23
1.11.7 Q22.7: State the de Broglie wavelength equation [1] . . . . . . . . . . 23
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, Paper 4 Essential Questions & Definitions 3
1.11.8 Q22.8: Explain wave-particle duality [2] . . . . . . . . . . . . . . . . 24
1.11.9 Q22.9: State what is meant by the de Broglie wavelength [1] . . . . . 24
1.12 Topic 23: Nuclear Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
1.12.1 Q23.1: Define the unified atomic mass unit (u) [1] . . . . . . . . . . . 25
1.12.2 Q23.2: Define mass defect [1] . . . . . . . . . . . . . . . . . . . . . . 25
1.12.3 Q23.3: Define binding energy [1] . . . . . . . . . . . . . . . . . . . . . 25
1.12.4 Q23.4: Define binding energy per nucleon [1] . . . . . . . . . . . . . . 26
1.12.5 Q23.5: Define radioactive decay [1] . . . . . . . . . . . . . . . . . . . 26
1.12.6 Q23.6: Define activity (of a radioactive source) [1] . . . . . . . . . . . 26
1.12.7 Q23.7: Define decay constant [1] . . . . . . . . . . . . . . . . . . . . . 27
1.12.8 Q23.8: Define half-life [1] . . . . . . . . . . . . . . . . . . . . . . . . . 27
1.12.9 Q23.9: State what is meant by random (in the context of radioactive
decay) [1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
1.12.10 Q23.10: State what is meant by spontaneous (in the context of ra-
dioactive decay) [1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
1.13 Topic 24: Medical Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
1.13.1 Q24.1: Define specific acoustic impedance [1] . . . . . . . . . . . . . . 28
1.13.2 Q24.2: Define attenuation [1] . . . . . . . . . . . . . . . . . . . . . . 28
1.13.3 Q24.3: Explain what is meant by a tracer [1] . . . . . . . . . . . . . . 29
1.13.4 Q24.4: Explain what is meant by annihilation [1] . . . . . . . . . . . 29
1.14 Topic 25: Astronomy and Cosmology . . . . . . . . . . . . . . . . . . . . . . 29
1.14.1 Q25.1: Define luminosity (of a star) [1] . . . . . . . . . . . . . . . . . 29
1.14.2 Q25.2: Define apparent brightness (intensity) [1] . . . . . . . . . . . . 30
1.14.3 Q25.3: State Hubble’s law [1] . . . . . . . . . . . . . . . . . . . . . . 30
1.14.4 Q25.4: Define redshift [1] . . . . . . . . . . . . . . . . . . . . . . . . . 30
1.14.5 Q25.5: State Wien’s displacement law [1] . . . . . . . . . . . . . . . . 30
1.14.6 Q25.6: State the Stefan-Boltzmann law [1] . . . . . . . . . . . . . . . 31
1.14.7 Q25.7: State what is meant by a standard candle [1] . . . . . . . . . 31
2 PART B: Most Repeated Calculation Questions 32
2.1 Topic 12: Circular Motion Calculations . . . . . . . . . . . . . . . . . . . . . 32
2.1.1 Q1: Angular Frequency and Centripetal Acceleration [2] . . . . . . . 32
2.2 Topic 13: Gravitational Fields Calculations . . . . . . . . . . . . . . . . . . . 33
2.2.1 Q2: Calculating Orbital Radius from Period [3] . . . . . . . . . . . . 33
2.2.2 Q3: Geostationary Satellite Height [3] . . . . . . . . . . . . . . . . . . 34
2.2.3 Q4: Change in Gravitational Potential Energy [3] . . . . . . . . . . . 35
Sciencetadium
