Topic 3 of 6 · 8 modules planned

Waves

What waves are, how light and sound behave and how the electromagnetic spectrum is used.

Modules

Module 1 · syllabus 3.1
Waves in a ripple tank
How do waves carry energy without carrying the water?
This module is planned. It will have readings, an experiment, practice with self-checks and a final check.

Syllabus statements for this topic · for teachers · 56 statements

Core for every pupil · Supplement also for Extended entry. Paraphrased from the Cambridge IGCSE Physics 0625 syllabus (2026–2028); check the official syllabus for exact wording.

3.1 General properties of waves

3.1.1Waves transfer energy, not matterC
3.1.2Wave motion in ropes, springs and waterC
3.1.3Wave features: wavefront, wavelength, frequency, amplitude, speedC
3.1.4Wave speed v = fλC
3.1.5Transverse waves and their examplesC
3.1.6Longitudinal waves and their examplesC
3.1.7Reflection, refraction and diffraction of wavesC
3.1.8Ripple tank demonstrations of wave behaviourC
3.1.9Diffraction through a gap: wavelength and gap sizeS
3.1.10Diffraction at an edge depends on wavelengthS

3.2.1 Reflection of light

3.2.1.1Normal, angle of incidence and angle of reflectionC
3.2.1.2Plane mirror image: same size, distance, virtualC
3.2.1.3Angle of incidence equals angle of reflectionC
3.2.1.4Constructions, measurements and calculations for plane mirrorsS

3.2.2 Refraction of light

3.2.2.1Normal, angle of incidence and angle of refractionC
3.2.2.2Refraction experiments with shaped transparent blocksC
3.2.2.3Light crossing a boundary between two mediaC
3.2.2.4Meaning of critical angleC
3.2.2.5Internal and total internal reflection examplesC
3.2.2.6Refractive index as a ratio of speedsS
3.2.2.7n = sin i / sin rS
3.2.2.8n = 1 / sin cS
3.2.2.9Optical fibres in telecommunicationsS

3.2.3 Thin lenses

3.2.3.1Converging and diverging lenses on parallel lightC
3.2.3.2Focal length, principal axis and principal focusC
3.2.3.3Ray diagrams: real image from a converging lensC
3.2.3.4Describing images: size, orientation, real or virtualC
3.2.3.5Virtual images from diverging rays traced backC
3.2.3.6Ray diagrams: virtual image from a converging lensS
3.2.3.7A single lens as a magnifying glassS
3.2.3.8Lenses correcting long and short sightS

3.2.4 Dispersion of light

3.2.4.1Dispersion of white light by a prismC
3.2.4.2Seven spectrum colours by frequency and wavelengthC
3.2.4.3Monochromatic light has one frequencyS

3.3 Electromagnetic spectrum

3.3.1Electromagnetic spectrum regions in orderC
3.3.2All electromagnetic waves share one vacuum speedC
3.3.3Uses of each electromagnetic regionC
3.3.4Harm from excessive electromagnetic exposureC
3.3.5Satellite communication by microwaves; low and geostationary orbitsC
3.3.6Speed of electromagnetic waves 3.0 × 10⁸ m/sS
3.3.7Why phones, Bluetooth and fibres use their wavesS
3.3.8Digital versus analogue signalsS
3.3.9Sound sent as a digital or analogue signalS
3.3.10Benefits of digital signallingS

3.4 Sound

3.4.1Sound from vibrating sourcesC
3.4.2Sound waves are longitudinalC
3.4.3Human hearing range 20 Hz to 20 kHzC
3.4.4Sound needs a mediumC
3.4.5Speed of sound in air about 330–350 m/sC
3.4.6Measuring the speed of sound from distance and timeC
3.4.7Amplitude and frequency versus loudness and pitchC
3.4.8An echo is reflected soundC
3.4.9Ultrasound is above 20 kHzC
3.4.10Compressions and rarefactionsS
3.4.11Sound speed in solids, liquids and gasesS
3.4.12Ultrasound uses; depth or distance from echo timeS