## Refractive index

It is a property of a medium which gives the idea of how much the light ray undergoes the refraction is known as refractive index. n=c/v

### Uses of refractive index

• Refractive index provides us information about the behaviour of the light. Refractive index of a substance increases and velocity decreases when light passes through different substances.
• There are many uses, refractive index is mostly used to identify a particular substance, to conform its purity or to measure its concentration.
• Refractive index is used to calculate the focusing power of a lens and also it is used for estimation of thermophysical properties of hydrocarbons and petroleum mixtures.

## How does refractive index vary with the wavelength?

According to the given definition of the refractive index, the speed of the light is the product of frequency and wavelength. Irrespective of the medium the frequency of the light wave remains unchanged. Whereas, the wavelength of the light wave changes based on the refraction. So, the refractive index varies with the wavelength.

### Is the speed of the light faster in glass or water?

The speed of the light is faster in water. 1.3 is the refractive index of water and the 1.5 is the refractive index of glass. From the given equation n=c/v we know that the refractive index of a medium is inversely proportional to the velocity of the light in that medium. So, it travels faster in the water.

 Material Refractive index Air 1.0003 Water 1.333 Diamond 2.417 Ice 1.31 Ethyl alcohol 1.36

#### Conclusion

This is some information about the refractive index of some substances. Which is very important for examination. It’s a very easy topic to understand and everyone can understand it very easily without any pressure. Everyone should learn its most important chapter and most important and very easy topic.