Refraction refers to the way that electromagnetic radiation (light) changes speed and direction as it travels across the boundary between one transparent medium and another.
- Light bends towards the normal and slows down when it moves from a fast medium (like air) to a slower medium (like water).
- Light bends away from the normal and speeds up when it moves from a slow medium (like diamond) to a faster medium (like glass).
- These phenomena are governed by Snell’s law, which describes the relationship between the angles of incidence and refraction.
- The refractive index (index of refraction) of a medium indicates how much the speed and direction of light are altered when travelling in or out of a medium.
- It is calculated by dividing the speed of light in a vacuum by the speed of light in the material.
- Snell’s law relates the angles of incidence and refraction to the refractive indices of the two media involved.
- Snell’s law states that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is equal to the ratio of the refractive indices.