Is it possible that (i) relative refractive index of the medium or (ii) absolute refractive index of the medium is less than unity ?

Explanation

To determine whether the relative refractive index or the absolute refractive index of a medium can be less than unity, we will analyze both concepts step by step.

### Step 1: Understanding Absolute Refractive Index
The absolute refractive index (n) of a medium is defined as the ratio of the speed of light in vacuum (c) to the speed of light in the medium (v). This is mathematically expressed as:

\[ n = \frac{c}{v} \]

### Step 2: Analyzing Absolute Refractive Index
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