IGCSE Physics

Overview

For parents: Cambridge International writes your child's Physics course and exams. Cambridge International (CAIE) sets the Cambridge IGCSE, taken in international schools in more than 150 countries. It uses its own specifications and grading.

Topics

Physics key terms

Original definitions for core course vocabulary, informed by the references below. Not an official or exhaustive board-specific glossary.

40 of 40 terms

Speed

The distance travelled per unit time; it is a scalar quantity.

Motion and forces

Velocity

The rate of change of displacement, with direction specified.

Motion and forces

Acceleration

The rate of change of velocity per unit time.

Motion and forces

Resultant force

The single force that has the same effect as all the forces acting on an object combined.

Motion and forces

Mass

A measure of an object's inertia, expressed in kilograms.

Motion and forces

Weight

The gravitational force on an object, equal to its mass multiplied by gravitational field strength.

Motion and forces

Momentum

The product of an object's mass and velocity; it is a vector quantity.

Motion and forces

Moment

The turning effect of a force, equal to force multiplied by the perpendicular distance from the pivot to its line of action.

Motion and forces

Density

Mass per unit volume of a substance.

Motion and forces

Pressure

The normal force acting per unit area of a surface.

Motion and forces

Work done

Energy transferred by a force acting through a distance; for a constant force along the motion, work equals force multiplied by distance.

Energy and thermal physics

Kinetic energy

The energy an object has because it is moving, equal to half its mass multiplied by its speed squared.

Energy and thermal physics

Gravitational potential energy

Energy associated with position in a gravitational field; near Earth's surface, a change is given by mass × gravitational field strength × change in height.

Energy and thermal physics

Power

The rate of energy transfer or work done per unit time.

Energy and thermal physics

Efficiency

The fraction of total energy input transferred usefully, often expressed as a percentage.

Energy and thermal physics

Specific heat capacity

The energy required to raise the temperature of one kilogram of a substance by one degree Celsius without changing its state.

Energy and thermal physics

Specific latent heat

The energy transferred per kilogram during a change of state without a temperature change.

Energy and thermal physics

Conduction

Thermal energy transfer through particle interactions, including energy transfer by free electrons in metals, without bulk movement of the material.

Energy and thermal physics

Convection

Thermal energy transfer by the bulk movement of a fluid caused by density differences.

Energy and thermal physics

Infrared radiation

Electromagnetic radiation with wavelengths longer than visible red light and shorter than microwaves, emitted by objects because of their temperature.

Energy and thermal physics

Wave

A disturbance that transfers energy without an overall transfer of matter.

Waves and optics

Amplitude

The maximum displacement of a point on a wave from its equilibrium position.

Waves and optics

Wavelength

The distance between successive points in phase, such as adjacent crests.

Waves and optics

Frequency

The number of complete oscillations or wave cycles per second, measured in hertz.

Waves and optics

Period

The time taken for one complete oscillation or wave cycle.

Waves and optics

Transverse wave

A wave in which oscillations are perpendicular to the direction of energy transfer.

Waves and optics

Longitudinal wave

A wave in which oscillations are parallel to the direction of energy transfer.

Waves and optics

Reflection

The return of a wave into its original medium after meeting a boundary.

Waves and optics

Refraction

A change in wave direction caused by a change in speed when crossing a boundary at an angle to the normal.

Waves and optics

Diffraction

The spreading of waves when they pass through a gap or around an obstacle.

Waves and optics

Electric current

The rate of flow of electric charge, measured in amperes.

Electricity, magnetism and atomic physics

Potential difference

The energy transferred per unit charge between two points in a circuit.

Electricity, magnetism and atomic physics

Resistance

The ratio of potential difference across a component to current through it, measured in ohms.

Electricity, magnetism and atomic physics

Electromotive force

The energy supplied by a source per unit charge passing through it.

Electricity, magnetism and atomic physics

Magnetic field

A region in which a magnetic pole, magnetic material or moving charge can experience a magnetic force.

Electricity, magnetism and atomic physics

Electromagnetic induction

The production of an electromotive force when the magnetic flux linked with a conductor changes.

Electricity, magnetism and atomic physics

Transformer

A device that uses electromagnetic induction between coils to change an alternating potential difference.

Electricity, magnetism and atomic physics

Radioactive decay

The spontaneous, random change of an unstable nucleus with emission of radiation.

Electricity, magnetism and atomic physics

Half-life

The time taken for the number of undecayed radioactive nuclei in a sample, or its activity, to fall to half its initial value.

Electricity, magnetism and atomic physics

Ionising radiation

Radiation with sufficient energy to remove electrons from atoms or molecules, forming ions.

Electricity, magnetism and atomic physics

Exams

Add your exam dates in My Exams and see a countdown for every paper on your dashboard.

Revision

Tell GCSE.es which Physics topics feel weak. Your dashboard then picks a short, timed next step — learn the key idea, check yourself, review mistakes.

Practice

• ✓ Key terms you tap to reveal
• ✓ Quick multiple-choice quizzes
• ✓ 3, 6, 9 and 12-mark exam-style questions
• ✓ Marking with feedback and a model answer

Available free inside your IGCSE journey. Questions are written by GCSE.es, not taken from real past papers.

Resources

Short, focused tasks for the Physics topics you find hardest — learn the key idea, check yourself, then try a marked exam-style question.