Refractive index

Refractive index

1. Refraction

   • The change of direction of light as it passes from one transparent substance into another
   • Takes place because waves change speed when they cross a boundary
     • The change in speed causes a change in direction
       • Unless the waves are travelling along a normal
   • Light ray will refract when it crosses from air into glass
     • Refracted towards the normal

2. A measure of how much the substance can refract a light ray

3. n = (sin i) / (sin r)

   • 'n' is the refractive index of the substance
   • 'sin i' is the sine of the angle of incidence
   • 'sin r' is the sine of the angle of refraction