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 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: \[ v = f \times \lambda \] where:
- \( v \) = speed of light in the medium
- \( f \) = frequency (constant)
- \( \lambda \) = wavelength

3. Why Wavelength Changes:

- Since the frequency \( f \) remains the same when light enters a new medium, any change in speed \( v \) must be accompanied by a change in wavelength \( \lambda \).
- 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.