Miscellaneous: Practice Problem & Solution

Solution Explained:

To solve this problem, we apply the core principles of Miscellaneous. Understanding the underlying formula is key to arriving at the correct answer below:

When light passes from one medium to another, its frequency $n$ remains constant as it depends on the source. The velocity of light decreases to $v' = \frac{v}{\mu}$, and correspondingly, the wavelength decreases to $\lambda' = \frac{\lambda}{\mu}$.