Relative Refractive index $n_{21}=$

The relative refractive index is a measure that compares the refractive index of one medium to another. It is defined as the ratio of the speed of light in one medium (medium 1) to the speed of light in another medium (medium 2). This concept is crucial in understanding how light bends or refracts when transitioning between different media.

Formula for Relative Refractive Index

The relative refractive index is mathematically expressed as:

n₂₁ = v₁ / v₂    

Where:

• n₂₁ is the relative refractive index of medium 2 with respect to medium 1.
• v₁ is the speed of light in medium 1.
• v₂ is the speed of light in medium 2.

How the Relative Refractive Index Works

The relative refractive index helps determine how much light will bend when passing from one medium to another. If the speed of light in medium 1 is greater than in medium 2, the relative refractive index will be greater than 1. If the speed of light in medium 1 is less than in medium 2, the relative refractive index will be less than 1. This ratio gives us a sense of how different media interact with light, affecting its speed and direction.

Importance of Relative Refractive Index

The relative refractive index plays a critical role in many optical applications, such as the design of lenses, fiber optics, and understanding the bending of light. It helps in predicting how light will behave at the interface between two media, which is essential in fields like physics, engineering, and materials science.