How does wavelength and frequency of a monochromatic light changes while travelling from one medium to another ?

Explanation

To understand how the wavelength and frequency of monochromatic light change when traveling from one medium to another, we can break down the explanation into several steps:

### Step-by-Step Solution:

1. **Definition of Monochromatic Light**:
- Monochromatic light consists of a single wavelength. For example, if we denote the wavelength in air (or vacuum) as \( \lambda_0 \).

2. **Understanding Refractive Index**:
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