Cambridge International · International A Level · 9702
Physics — Keywords & Key Terms — Definitions Glossary (2026)
Cambridge International A Level Physics (9702)
Topic-by-topic keywords, key terms and definitions for precise exam language—separate from our revision checklists (topic coverage) and formula sheets (equations).
Keywords & Key Terms — definitions
Examiner-style keywords and definitions organised by syllabus topic. Terms are tagged Essential (start here), Core (typical exam standard), and Advanced for harder distinctions — tick each row when you can recall it. Your progress is saved in this browser for this list.
Cambridge International International A Level Physics (9702)
Cambridge International International A Level Physics (9702)
Cambridge International A Level Physics (9702)
Structured around Cambridge 9702 topic areas: physical quantities, mechanics, materials, waves, superposition, electricity, fields, thermal physics, ideal gases, nuclear physics, quantum physics, medical physics and astrophysics (according to your chosen options). AS content is assessed in Paper 1/2/3; A Level adds Paper 4 and options in Paper 5 — confirm your entry route.
Mark schemes: Cambridge rewards precise definitions, algebra shown step-by-step with substituted values, and consistent SI units. Definitions of quantities should match standard form (e.g. field as force per unit …). Practical papers: combined uncertainty, correct significant figures, linearising graphs, interpreting gradient and intercept physically, and structured evaluation (systematic vs random, improvements).
Active recall: 0 / 94 terms ticked
| Recalled | Topic | Level | Keyword | Definition |
|---|---|---|---|---|
| Physical quantities, units & uncertainties | Essential | Base quantity | One of seven SI base quantities (e.g. length, mass, time, current). | |
| Physical quantities, units & uncertainties | Core | Derived quantity | Defined as a product or quotient of base quantities (e.g. force, energy). | |
| Physical quantities, units & uncertainties | Core | Homogeneity of equations | Both sides of a physical equation must have the same base dimensions. | |
| Physical quantities, units & uncertainties | Core | Scalar | Fully described by magnitude only. | |
| Physical quantities, units & uncertainties | Core | Vector | Described by magnitude and direction; adds by vector rules. | |
| Physical quantities, units & uncertainties | Core | Uncertainty | Interval within which the true value is expected to lie. | |
| Physical quantities, units & uncertainties | Core | Precision | Closeness of repeated measurements — reflects random error. | |
| Physical quantities, units & uncertainties | Core | Accuracy | Closeness to accepted/true value — reflects systematic error. | |
| Physical quantities, units & uncertainties | Advanced | Fractional / percentage uncertainty | Uncertainty ÷ measured value — combines for products/quotients by addition. | |
| Physical quantities, units & uncertainties | Advanced | Combining uncertainties | Sum/difference: add absolute uncertainties; product/quotient: add fractional uncertainties. | |
| Kinematics & linear motion | Core | Displacement | Vector from initial to final position. | |
| Kinematics & linear motion | Core | Velocity | Rate of change of displacement — vector. | |
| Kinematics & linear motion | Core | Speed | Magnitude of velocity or distance ÷ time for uniform motion. | |
| Kinematics & linear motion | Core | Acceleration | Rate of change of velocity. | |
| Kinematics & linear motion | Core | suvat equations | Constant acceleration kinematic relations. | |
| Kinematics & linear motion | Core | Projectile motion | Horizontal motion uniform; vertical motion uniform acceleration — independence of components. | |
| Kinematics & linear motion | Advanced | Relative velocity | Vector difference of velocities in different frames. | |
| Dynamics, momentum & energy | Core | Newton’s first law | Body remains at rest or uniform velocity unless resultant force acts. | |
| Dynamics, momentum & energy | Core | Newton’s second law | Resultant F = dp/dt; for constant mass F = ma. | |
| Dynamics, momentum & energy | Core | Newton’s third law | Forces on two interacting bodies are equal, opposite, same type, different bodies. | |
| Dynamics, momentum & energy | Core | Linear momentum | p = mv — vector conserved if no external resultant force. | |
| Dynamics, momentum & energy | Core | Impulse | ∫F dt = Δp; area under F–t graph. | |
| Dynamics, momentum & energy | Core | Work | W = ∫F·ds; constant force W = Fs cos θ. | |
| Dynamics, momentum & energy | Core | Kinetic energy | ½mv² for non-relativistic particle. | |
| Dynamics, momentum & energy | Core | Gravitational potential energy | Work done to move to point in field from reference. | |
| Dynamics, momentum & energy | Core | Power | Rate of doing work or rate of energy transfer. | |
| Dynamics, momentum & energy | Advanced | Elastic & inelastic collisions | Momentum conserved in isolated system; KE only conserved if elastic. | |
| Dynamics, momentum & energy | Core | Principle of conservation of energy | Total energy of isolated system constant — energy transformed between stores. | |
| Forces, moments & materials | Core | Moment | Force × perpendicular distance to pivot. | |
| Forces, moments & materials | Core | Couple | Pair of equal, opposite, non-collinear forces — produces torque. | |
| Forces, moments & materials | Core | Torque | Moment of a couple; turning effect. | |
| Forces, moments & materials | Core | Centre of gravity | Point where weight appears to act. | |
| Forces, moments & materials | Core | Density | Mass per unit volume. | |
| Forces, moments & materials | Core | Pressure | Force per unit area in fluids: p = F/A. | |
| Forces, moments & materials | Advanced | Upthrust | Equals weight of fluid displaced — Archimedes’ principle. | |
| Forces, moments & materials | Core | Stress | Force per unit cross-sectional area. | |
| Forces, moments & materials | Core | Strain | Extension ÷ original length for tensile. | |
| Forces, moments & materials | Core | Young modulus | Stress ÷ strain in elastic region. | |
| Forces, moments & materials | Core | Elastic limit | Beyond which material does not return to original shape. | |
| Forces, moments & materials | Advanced | Strain energy | Area under force–extension graph in elastic region. | |
| Circular motion, gravitation & oscillations | Core | Centripetal acceleration | v²/r toward centre of circular path. | |
| Circular motion, gravitation & oscillations | Core | Centripetal force | Resultant toward centre causing circular motion. | |
| Circular motion, gravitation & oscillations | Core | Newton’s law of gravitation | F = GMm/r² between point masses. | |
| Circular motion, gravitation & oscillations | Core | Gravitational field strength | Force per unit mass at a point. | |
| Circular motion, gravitation & oscillations | Core | Gravitational potential | Work per unit mass to move from infinity. | |
| Circular motion, gravitation & oscillations | Advanced | Geostationary orbit | Equatorial orbit with period 24 h; satellite fixed above Earth point. | |
| Circular motion, gravitation & oscillations | Core | Simple harmonic motion | Acceleration ∝ displacement toward equilibrium; a = −ω²x. | |
| Circular motion, gravitation & oscillations | Core | Angular frequency | ω = 2πf = 2π/T. | |
| Circular motion, gravitation & oscillations | Core | Damping | Energy lost to surroundings — amplitude decays. | |
| Circular motion, gravitation & oscillations | Advanced | Forced oscillations & resonance | Maximum amplitude when driving frequency ≈ natural frequency. | |
| Thermal physics & ideal gases | Core | Internal energy | Sum of random kinetic and potential energies of molecules. | |
| Thermal physics & ideal gases | Core | First law of thermodynamics | ΔU = Q + W (sign conventions for heat in/out and work by/on system). | |
| Thermal physics & ideal gases | Core | Specific heat capacity | Energy to raise 1 kg by 1 K. | |
| Thermal physics & ideal gases | Core | Molar heat capacity | Heat per mole per K. | |
| Thermal physics & ideal gases | Core | Ideal gas equation | pV = nRT for ideal gas. | |
| Thermal physics & ideal gases | Core | Kinetic theory assumptions | Point molecules; elastic collisions; large number; random motion. | |
| Thermal physics & ideal gases | Advanced | Root-mean-square speed | Related to mean kinetic energy — ½mc² = 3/2 kT for monatomic ideal gas. | |
| Electric fields, potential & capacitors | Core | Electric field strength | Force per unit positive test charge — vector. | |
| Electric fields, potential & capacitors | Core | Uniform field between parallel plates | E = V/d. | |
| Electric fields, potential & capacitors | Core | Electric potential | Work per unit positive charge from infinity. | |
| Electric fields, potential & capacitors | Core | Potential difference | Work per unit charge between two points. | |
| Electric fields, potential & capacitors | Core | Coulomb’s law | Force between point charges in vacuum. | |
| Electric fields, potential & capacitors | Core | Capacitance | C = Q/V for isolated conductor or capacitor. | |
| Electric fields, potential & capacitors | Core | Energy stored | ½CV² = ½Q²/C = ½QV. | |
| Electric fields, potential & capacitors | Advanced | Capacitors in series/parallel | Reciprocal sum for series; sum for parallel. | |
| Electric fields, potential & capacitors | Core | RC time constant | τ = RC — charging/discharging exponential curves. | |
| Magnetic fields & electromagnetic induction | Core | Magnetic flux density B | Defined via F = BIl sin θ on current-carrying conductor. | |
| Magnetic fields & electromagnetic induction | Core | Magnetic flux | Φ = BA cos θ through area. | |
| Magnetic fields & electromagnetic induction | Core | Magnetic flux linkage | NΦ for coil of N turns. | |
| Magnetic fields & electromagnetic induction | Core | Force on moving charge | F = Bqv sin θ. | |
| Magnetic fields & electromagnetic induction | Core | Hall effect | Build-up of p.d. across conductor in B field — charge carriers deflected. | |
| Magnetic fields & electromagnetic induction | Advanced | Faraday’s law | Induced e.m.f. magnitude ∝ rate of change of magnetic flux linkage. | |
| Magnetic fields & electromagnetic induction | Advanced | Lenz’s law | Direction of induced current opposes change producing it. | |
| Magnetic fields & electromagnetic induction | Core | Root-mean-square values | For sinusoidal current/voltage — Irms = I₀/√2. | |
| Magnetic fields & electromagnetic induction | Core | Transformer | Alternating flux in core induces e.m.f. in secondary — voltage ratio ≈ turns ratio for ideal. | |
| Waves, superposition & optics | Core | Progressive wave | Energy transfer without net medium displacement over a cycle. | |
| Waves, superposition & optics | Core | Phase difference | Fraction of a cycle between two oscillating points. | |
| Waves, superposition & optics | Core | Superposition | Resultant displacement = sum of individual displacements. | |
| Waves, superposition & optics | Core | Interference | Constructive when path difference = nλ; destructive when (n+½)λ (conditions depend on geometry). | |
| Waves, superposition & optics | Core | Diffraction | Spreading when obstacle/gap comparable to wavelength. | |
| Waves, superposition & optics | Core | Two-slit interference | Fringe spacing λD/a for small angles. | |
| Waves, superposition & optics | Core | Diffraction grating | nλ = d sin θ for spectral lines. | |
| Waves, superposition & optics | Core | Stationary waves | Nodes (zero amplitude) and antinodes (max amplitude). | |
| Waves, superposition & optics | Advanced | Polarisation | Transverse waves — oscillation in one plane; filter selects component. | |
| Quantum physics & nuclear physics | Core | Photon | Quantum of electromagnetic energy E = hf. | |
| Quantum physics & nuclear physics | Core | Photoelectric effect | hf = φ + KEmax; threshold frequency f₀ = φ/h. | |
| Quantum physics & nuclear physics | Core | de Broglie wavelength | λ = h/p. | |
| Quantum physics & nuclear physics | Core | Energy levels | Electrons in isolated atoms have discrete energies — line spectra. | |
| Quantum physics & nuclear physics | Core | Radioactive decay | Spontaneous, random; activity A = −dN/d = λN. | |
| Quantum physics & nuclear physics | Core | Decay constant λ | Probability of decay per unit time. | |
| Quantum physics & nuclear physics | Core | Half-life | t½ = ln 2/λ — time for activity or N to halve. | |
| Quantum physics & nuclear physics | Core | Alpha, beta minus, beta plus, gamma | Properties, ionisation, penetration, conservation in equations. | |
| Quantum physics & nuclear physics | Advanced | Mass defect | Difference between nucleus mass and sum of nucleon masses — binding energy via E = mc². | |
| Quantum physics & nuclear physics | Advanced | Binding energy per nucleon curve | Maximum near Fe — energy released in fusion (light) and fission (heavy). |
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Physics (9702) — Keywords & Key Terms FAQ
- What is on this Cambridge International International A Level Physics keywords and key terms list?
- It is a topic-organised glossary of important physics terms with short, exam-style definitions aligned to Cambridge International A Level Physics (9702) (9702). It is designed for “define”, “state”, “outline” and “explain” questions where precise vocabulary earns marks.
- How should I use this Physics glossary alongside past papers?
- Tick terms when you can recall them without reading the answer, then check your wording against mark schemes. Pair vocabulary practice with past papers for International A Level Physics (9702) so you apply terms in context.
- Is this the same as a revision checklist or a formula sheet?
- No. Revision checklists help you track which syllabus topics you have covered and your confidence—separate pages on Tutopiya. Formula sheets summarise equations and quantitative relationships. This page is only a definitions and key-terms glossary for Physics. Quantitative relationships belong on formula sheets; this list emphasises language and concepts.
- Can I download this Physics keywords and key terms list for free?
- Yes. After a quick free sign-up you can download a UTF-8 CSV (opens in Excel or Google Sheets) or open a print-friendly page and save as PDF. Browsing the list on the page is free.
- Is this Physics list aligned to the 9702 specification?
- Topic groupings and wording follow Cambridge International A Level Physics (9702) for Cambridge International International A Level. Always confirm final learning objectives and any regional options in your official specification and recent examiner reports for your exam session.
- Why focus on definitions instead of full notes?
- Mark schemes reward correct technical terms and clear links between ideas. A compact glossary lets you drill the exact language examiners expect for Physics at International A Level, separate from longer notes or topic trackers.