AQA · International A Level · HL/SL
Physics — Keywords & Key Terms — Definitions Glossary (2026)
IB Diploma Programme Physics (HL/SL)
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.
IB Diploma Programme Physics (HL/SL)
IB Diploma Programme Physics (HL/SL)
IB Diploma Programme Physics (HL/SL)
Topics follow the IB DP Physics syllabus (first assessment 2025). The IB data booklet provides equations — keywords focus on conceptual understanding, definitions and the ability to apply principles.
Mark schemes: IB Physics demands precise language: 'rate of change of velocity' not 'getting faster'. State the law or principle first, then apply it. Equations must have units on every line.
Active recall: 0 / 46 terms ticked
| Recalled | Topic | Level | Keyword | Definition |
|---|---|---|---|---|
| Mechanics | Essential | Scalar | Physical quantity with magnitude only (e.g. distance, speed, mass, time, energy). | |
| Mechanics | Essential | Vector | Physical quantity with both magnitude and direction (e.g. displacement, velocity, acceleration, force). | |
| Mechanics | Core | Displacement | Change in position from a reference point; vector quantity (m). | |
| Mechanics | Core | Velocity | Rate of change of displacement with time; vector (m/s). | |
| Mechanics | Core | Acceleration | Rate of change of velocity with time; vector (m/s²). | |
| Mechanics | Core | Newton's first law | An object remains at rest or constant velocity unless acted on by a resultant force. | |
| Mechanics | Core | Newton's second law | The resultant force on an object equals its rate of change of momentum: F = ma (for constant mass). | |
| Mechanics | Core | Newton's third law | When object A exerts a force on object B, object B exerts an equal and opposite force on object A. Forces are the same type, act on different objects. | |
| Mechanics | Core | Linear momentum | p = mv; conserved in a closed system (no external resultant force). | |
| Mechanics | Core | Impulse | Change in momentum; equal to force × time: J = FΔt. | |
| Mechanics | Core | Kinetic energy | Energy due to motion: Ek = ½mv². | |
| Mechanics | Core | Gravitational potential energy | Energy stored in a gravitational field: Ep = mgh (near Earth's surface). | |
| Mechanics | Core | Work-energy theorem | Net work done on an object equals its change in kinetic energy. | |
| Mechanics | Advanced | Centre of mass | Point where the entire mass of a system can be considered to act for the purpose of analysing translational motion. | |
| Waves | Essential | Wave | Transfer of energy through a medium (or vacuum for EM waves) without net transfer of matter. | |
| Waves | Core | Transverse wave | Wave in which oscillation is perpendicular to the direction of energy transfer (e.g. light, water). | |
| Waves | Core | Longitudinal wave | Wave in which oscillation is parallel to the direction of energy transfer (e.g. sound, P-waves). | |
| Waves | Core | Amplitude | Maximum displacement of a particle from equilibrium position; related to wave energy. | |
| Waves | Core | Frequency (f) | Number of complete oscillations per unit time; measured in Hz. | |
| Waves | Core | Wavelength (λ) | Distance between two adjacent points in phase (e.g. crest to crest). | |
| Waves | Core | Wave speed (v) | Speed at which the wave pattern propagates: v = fλ. | |
| Waves | Core | Superposition | When two or more waves meet, the resultant displacement equals the sum of individual displacements. | |
| Waves | Core | Diffraction | Spreading of waves as they pass through a gap or around an obstacle; most significant when gap ≈ wavelength. | |
| Waves | Core | Interference | Superposition of coherent waves producing regions of constructive (in phase) and destructive (out of phase) combination. | |
| Waves | Core | Doppler effect | Change in observed frequency when source or observer moves relative to each other. | |
| Waves | Advanced | Standing wave | Stationary pattern formed by superposition of two identical waves travelling in opposite directions; has nodes (zero displacement) and antinodes (maximum displacement). | |
| Electricity and Magnetism | Essential | Electric charge (Q) | Fundamental property of matter; measured in coulombs (C). Like charges repel, opposite charges attract. | |
| Electricity and Magnetism | Core | Electric current (I) | Rate of flow of charge: I = Q/t; measured in amperes (A). | |
| Electricity and Magnetism | Core | Potential difference (V) | Work done per unit charge moved between two points: V = W/Q; measured in volts (V). | |
| Electricity and Magnetism | Core | Resistance (R) | Opposition to current flow: R = V/I; measured in ohms (Ω). | |
| Electricity and Magnetism | Core | Ohm's law | Current is directly proportional to potential difference at constant temperature: V = IR. | |
| Electricity and Magnetism | Core | Electromotive force (EMF) | Energy supplied per unit charge by a source of electrical energy; measured in volts (V). | |
| Electricity and Magnetism | Core | Internal resistance | Resistance within a source of EMF; causes terminal voltage to be less than EMF under load. | |
| Electricity and Magnetism | Core | Kirchhoff's current law | Sum of currents entering a junction equals sum of currents leaving; conservation of charge. | |
| Electricity and Magnetism | Core | Kirchhoff's voltage law | Sum of EMFs around a closed loop equals sum of potential differences; conservation of energy. | |
| Electricity and Magnetism | Advanced | Magnetic flux (Φ) | Measure of magnetic field passing through a surface: Φ = BA cos θ; measured in webers (Wb). | |
| Electricity and Magnetism | Advanced | Faraday's law | Magnitude of induced EMF equals rate of change of magnetic flux linkage. | |
| Electricity and Magnetism | Advanced | Lenz's law | Induced current flows in a direction to oppose the change causing it; conservation of energy. | |
| Thermal Physics | Essential | Temperature | Measure of the average kinetic energy of particles in a substance. | |
| Thermal Physics | Core | Internal energy | Total kinetic energy and potential energy of all particles in a substance. | |
| Thermal Physics | Core | Specific heat capacity (c) | Energy required to raise the temperature of 1 kg of a substance by 1 K: Q = mcΔT. | |
| Thermal Physics | Core | Specific latent heat (L) | Energy required to change the state of 1 kg of a substance without changing its temperature: Q = mL. | |
| Thermal Physics | Core | Ideal gas | Theoretical gas where particles have no volume, no intermolecular forces, and collisions are perfectly elastic. | |
| Thermal Physics | Core | Ideal gas law | PV = nRT; P = pressure (Pa), V = volume (m³), n = moles, R = 8.31 J mol⁻¹ K⁻¹, T = temperature (K). | |
| Thermal Physics | Advanced | First law of thermodynamics | ΔU = Q + W; change in internal energy equals heat added to system plus work done on system. | |
| Thermal Physics | Advanced | Second law of thermodynamics | Entropy of an isolated system always increases; heat cannot spontaneously flow from cold to hot. |
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Physics (HL/SL) — Keywords & Key Terms FAQ
- What is on this AQA 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 IB Diploma Programme Physics (HL/SL) (HL/SL). 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 (HL/SL) 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 HL/SL specification?
- Topic groupings and wording follow IB Diploma Programme Physics (HL/SL) for AQA 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.