Light

To solve the problem, we need to understand what happens to light when it passes from one medium to another and why its wavelength changes.

1. Understanding the Behavior of Light:

- Light travels as a wave characterized by its speed, wavelength, and frequency.
- When light moves from one medium to another (e.g., from air to water), its speed changes due to the properties of the medium.
- The frequency of light remains constant because it is determined by the source of light and does not change during transmission.

2. Relationship Between Speed, Wavelength, and Frequency:

The relationship is given by the equation: where:
- = speed of light in the medium
- = frequency (constant)
- = wavelength

3. Why Wavelength Changes:

- Since the frequency remains the same when light enters a new medium, any change in speed must be accompanied by a change in wavelength .
- When light slows down entering a denser medium, its wavelength decreases.
- When light speeds up entering a less dense medium, its wavelength increases.

Final Answer:

The wavelength of light changes when it enters a different medium because the speed of light changes while the frequency remains constant.