Welcome! Today we'll explore the concept of refractive index. Refractive index is a fundamental property of materials that describes how light behaves when it passes through them. It measures how much a medium slows down light and bends its path compared to vacuum.
The refractive index is mathematically defined as n equals c divided by v, where n is the refractive index, c is the speed of light in vacuum which is approximately 3 times 10 to the 8 meters per second, and v is the speed of light in the medium. Since light always travels slower in any medium than in vacuum, the refractive index is always greater than 1.
When light travels from one medium to another, it changes direction according to Snell's Law. This law states that n1 times sine of theta 1 equals n2 times sine of theta 2, where theta 1 is the incident angle and theta 2 is the refracted angle. The amount of bending depends on the difference in refractive indices between the two media.
Different materials have different refractive indices. Air has a refractive index very close to 1, water is about 1.33, ordinary glass is around 1.5, and diamond has a high refractive index of about 2.42. The higher the refractive index, the more the light bends when entering the material. This is why diamonds sparkle so brilliantly - their high refractive index causes significant light bending.
To summarize what we've learned about refractive index: It's a fundamental property that measures how much materials slow down and bend light. The mathematical formula is n equals c over v. Light changes direction according to Snell's Law when moving between media. Higher refractive indices cause more bending, which explains phenomena like the brilliance of diamonds and enables technologies like lenses and optical fibers.