Edexcel iGCSE Physics -3.3 Wave Terminology- Study Notes- New Syllabus

Key Wave Definitions

Waves are described using specific terms that define how they move and how energy is transferred. Understanding these definitions is essential for analysing wave behaviour and solving wave problems at IGCSE level.

Amplitude

The amplitude of a wave is the maximum displacement of a point on the wave from its undisturbed (equilibrium) position.

• Measured in metres (m).
• Indicates the energy carried by the wave.
• Greater amplitude → more energy.

Wavelength

The wavelength is the distance between two successive points on a wave that are in the same phase.

• Measured in metres (m).
• Crest to crest (transverse).
• Compression to compression (longitudinal).

Symbol: \( \mathrm{\lambda} \)

Frequency

The frequency of a wave is the number of complete waves (oscillations) passing a point each second.

• Measured in hertz (Hz).
• 1 Hz = 1 wave per second.

Symbol: \( \mathrm{f} \)

Period

The period of a wave is the time taken for one complete wave (oscillation).

• Measured in seconds (s).
• Inverse of frequency.

Relationship:

\( \mathrm{T = \dfrac{1}{f}} \)

Wavefront

A wavefront is a line (or surface) joining points on a wave that are in the same phase of vibration.

• Plane wavefronts → straight, parallel lines.
• Circular wavefronts → concentric circles.
• Direction of wave travel is perpendicular to wavefronts.

Key Wave Relationships

\( \mathrm{wave\ speed = frequency \times wavelength} \)

\( \mathrm{v = f\lambda} \)

• \( \mathrm{v} \) = wave speed (m/s)
• \( \mathrm{f} \) = frequency (Hz)
• \( \mathrm{\lambda} \) = wavelength (m)

Key Idea

• Wave properties describe energy transfer.
• Frequency and period are linked.
• Wavelength depends on speed and frequency.

Important Points to Remember

• Do not confuse wavelength with amplitude.
• Always include correct units.
• Wavefronts show wave direction.