# (AQA GCSE P3.1.3) Refractive Index

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• Created by: Em
• Created on: 20-04-13 00:01
• Refractive Index
• Each medium which light can pass through has a different refractive index. This is what determines the angle the ray of light will change direction (bend) at.
• The first, initial ray which hits the medium is called the incident ray.
• The refractive index of a material is a feature which states how the light rays would refract when they hit it.
• The NORMAL line is an imaginary line which is at 90 degrees to the surface of the material the light is hitting.
• The angle of incidence (i) is the angle at which the light hits the material compared to the normal.
• The angle of refraction (r) is the angle at which the light passes through the material compared to the normal (i.e. the angle will be smaller or larger than the angle of incidence)
• REFRACTIVE INDEX = sin i / sin r
• For example, if the angle of incidence is 10.0 and the angle of refraction is 6.5, the calculation would be sin(10) divided by (or over as a fraction) sin(6.5) which would equal a refractive index of 1.54