Stage 6 Physics: Module 3 — Waves
Submodule 1: Wave Properties (Study Guide)
1. Introduction to Wave Motion
A wave is a disturbance that transfers energy from one point to another through space or a medium without transferring matter.
The Key Principle
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Particles of the medium oscillate (vibrate) locally around a fixed equilibrium position.
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The wave energy travels continuously forward.
2. Mechanical vs. Electromagnetic Waves
Waves are broadly classified based on whether they require a physical medium to propagate.
| Property | Mechanical Waves | Electromagnetic (EM) Waves |
| Medium Requirement | Must have a physical medium (solid, liquid, or gas). Cannot travel through a vacuum. | Can travel through a vacuum and through transparent media. |
| Mechanism | Relies on the elastic properties and particle interactions of the medium. | Relies on oscillating, mutually perpendicular electric and magnetic fields. |
| Speed | Relatively slow (e.g., sound in air $\approx$ 340 m/s). | Travels at the speed of light ($c \approx 3 \times 10^8 \text{ m/s}$ in a vacuum). |
| Examples | Sound waves, water waves, seismic S and P waves, vibrating strings. | Light, X-rays, Microwaves, Radio waves, UV radiation. |
3. Wave Classification: Transverse vs. Longitudinal
Waves are categorized by how the direction of particle oscillation compares to the direction of wave energy transfer.
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