Wave Properties
Year 9 🌊 Waves & Optics Describe amplitude, frequency, wavelength; use v = fλ.
🌊 Describing Waves
Waves transfer energy without transferring matter. Key terms:
| Term | Definition | Unit |
|---|---|---|
| Amplitude (A) | Maximum displacement from equilibrium | m |
| Wavelength (λ) | Distance between two successive identical points | m |
| Frequency (f) | Number of complete waves per second | Hz |
| Period (T) | Time for one complete wave | s |
| Wave speed (v) | Distance travelled per second | m/s |
⚡ The Wave Equation
Wave speed, frequency and wavelength are linked.
⚡ Wave Equation
$$v = f\lambda \qquad T = \frac{1}{f}$$Example: A sound wave has f = 340 Hz and λ = 1 m → v = 340 × 1 = 340 m/s
↔️ Transverse & Longitudinal Waves
Transverse waves: vibrations are perpendicular to direction of travel (e.g. light, water waves). Longitudinal waves: vibrations are parallel to direction of travel (e.g. sound).
Sound is longitudinal — the particles vibrate back and forth (compressions and rarefactions), not up and down.
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