in refrective index there is any medium will taken to take out the index while in absolute refrective index there must one medium is either air or vacuum then it is said to be absolute refrective index

Refractive Index vs Absolute Refractive Index
The refractive index is a fundamental property of a material that describes how light propagates through it. It is defined as the ratio of the speed of light in a vacuum to the speed of light in the material. On the other hand, absolute refractive index is a specific value that quantifies the refractive index of a material with respect to a standard medium, typically air or vacuum.

Refractive Index:
- Refractive index is a dimensionless quantity that characterizes how much a material bends or refracts light.
- It is calculated by dividing the speed of light in a vacuum by the speed of light in the material.
- Refractive index varies with wavelength of light and temperature of the material.
- It is denoted by the symbol 'n' and is used to calculate the angle of refraction when light enters a different medium.

Absolute Refractive Index:
- Absolute refractive index is a specific value that represents the refractive index of a material with respect to a standard medium, usually air or vacuum.
- It is a constant value for a given material at a specific wavelength of light.
- Absolute refractive index provides a standardized measure for comparing the refractive properties of different materials.
- It is often used in optical calculations and design of lenses, prisms, and other optical components.
In summary, the refractive index is a general term that describes how light interacts with a material, while absolute refractive index is a specific value that quantifies this interaction with respect to a standard medium. Both concepts are important in the field of optics and play a crucial role in understanding the behavior of light in different materials.