Wave properties · Year 12
Waves carry energy from place to place without carrying the material along. In a transverse wave (light, ripples, waves on a string) the vibrations are at right angles to the direction of travel; in a longitudinal wave (sound) they are along it. Every wave obeys the same equation: speed = frequency × wavelength.
Key facts
- Amplitude: from the rest line to a crest. Wavelength λ: from one crest to the next.
- Frequency f: waves per second (Hz). Period T = 1 ÷ f.
- v = f λ.
- Transverse: vibrations ⊥ direction of travel. Longitudinal: vibrations ∥ direction of travel.
- When a wave changes medium, its frequency stays the same; speed and wavelength change.
- Phase difference = (separation ÷ λ) × 360°.