2 million km per second 20 km per second 20 000 km per second 200 000 km per second
Relational Index Reflective Index Dispersive Index Refractive Index
30 metres per second 5000 metres per second 1400 metres per second 330 metres per second
Dispersion Diffusion Interference Diffraction
X-Rays Ultrafast Waves Light Waves Ultrasonic Waves
3 million km per second 30 km per second 30 000 km per second 300 000 km per second
Diamond Glass Water Perspex