Calculate wave properties and visualize waveforms
The wave equation describes how waves propagate through different media. For a sinusoidal wave traveling in the x-direction, the wave function is:
| Wave Type | Frequency | Wavelength | Speed |
|---|---|---|---|
| Ocean wave | 0.1 Hz | 100 m | 10 m/s |
| Sound wave (air) | 440 Hz | 0.78 m | 343 m/s |
| Light wave (red) | 4.3×10¹⁴ Hz | 700 nm | 3×10⁸ m/s |
| Radio wave (FM) | 100 MHz | 3 m | 3×10⁸ m/s |
| Seismic wave | 0.05 Hz | 20 km | 1000 m/s |
Reflection: Waves bouncing off surfaces. Examples: Echoes, mirrors.
Refraction: Waves changing direction when entering different media. Examples: Lens focusing, mirages.
Diffraction: Waves spreading out when passing through openings. Examples: Sound around corners, CD rainbow patterns.
Interference: Waves combining constructively or destructively. Examples: Noise-canceling headphones, soap bubbles.
Frequency and wavelength are inversely proportional through the wave equation:
Where v is the wave speed. This means:
For electromagnetic waves in vacuum, v = c (speed of light), so:
This relationship explains why radio waves have long wavelengths (meters to kilometers) while gamma rays have extremely short wavelengths (picometers).
Wave speed depends on the properties of the medium:
Generally, wave speed increases with stiffness and decreases with density.
Phase velocity and group velocity describe different aspects of wave propagation:
| Parameter | Phase Velocity | Group Velocity |
|---|---|---|
| Definition | Speed of a single wave crest | Speed of wave packet envelope |
| Formula | v_p = ω/k | v_g = dω/dk |
| Relation | v_g = v_p + k(dv_p/dk) | |
| Dispersion | Can exceed c in some media | Speed of information transfer |
| Application | Monochromatic waves | Wave packets, signals |
In non-dispersive media (like vacuum for light), v_p = v_g. In dispersive media (like glass for light), v_p ≠ v_g.
Standing waves form when two waves of the same frequency and amplitude travel in opposite directions and interfere:
Standing wave equation:
Applications: