Question

When light enters a different medium, its wavelength changes because:

• A. The frequency of the light changes.
• B. The speed of light changes in the new medium.
• C. The energy of the light changes.
• D. The color of the light changes.

Answer 1

The Correct Option is B

To address the problem, we must first grasp how light behaves when transitioning between media and the reasons for its wavelength alteration.

1. Understanding Light's Behavior:

- Light propagates as a wave, defined by its velocity, wavelength, and frequency.
- Upon entering a new medium (e.g., from air to water), light's velocity is modified by the medium's characteristics.
- The frequency of light is invariant, being dictated by the light source and unaltered during propagation.

2. Interrelation of Speed, Wavelength, and Frequency:

The governing equation is: \[v = f \times \lambda\] wherein: - \( v \) denotes the speed of light within the medium. - \( f \) represents the frequency (constant). - \( \lambda \) signifies the wavelength.

3. Rationale for Wavelength Change:

- Given that light's frequency \( f \) remains constant upon entering a new medium, any fluctuation in speed \( v \) necessitates a corresponding alteration in wavelength \( \lambda \).
- As light decelerates upon entering a denser medium, its wavelength diminishes.
- Conversely, as light accelerates upon entering a less dense medium, its wavelength increases.

Final Answer:

The wavelength of light undergoes modification when it passes into a different medium due to a change in the speed of light while its frequency remains constant.