Waves · revision map · IGCSE 0625, Topic 3.1
TOPIC 3.1 · WAVES
CAMBRIDGE IGCSE PHYSICS 0625 · ONE-PAGE REVISION MAP
thelucidstem.com
WAVES3.1
Describing a Wave
A wave transfers energy without transferring matter.
- Amplitude: maximum distance from rest.
- Wavelength λ: crest to next crest.
- Frequency f: waves per second, in hertz (Hz).
- Wavefront: a line joining points in step.
The Wave Equation
Wave speed links how often and how far apart the waves are.
v = f λ
T = 1 / f
v = wave speed (m/s), f = frequency (Hz), λ = wavelength (m), T = period (s)
- The period T is the time for one complete wave.
Transverse vs Longitudinal
Transverse: vibration at 90° to the direction of travel.
Longitudinal: vibration along the direction of travel (compressions and rarefactions).
Reflection & Refraction
Waves change direction when they meet a surface or a boundary.
- Reflection: bounces off a barrier; the angle of incidence equals the angle of reflection (i = r).
- Refraction: the speed changes at a boundary, so the wave bends. Slowing bends it toward the normal.
- In refraction the frequency stays the same; the speed and wavelength change.
The Ripple Tank
A ripple tank shows wave behaviour with water waves.
- Shows reflection, refraction (over a shallow region) and diffraction.
DiffractionEXTENDED
Waves spread out as they pass through a gap or around an edge.
- Greatest when the gap is about one wavelength wide.
- The wavelength does not change; only direction and spreading do.