Which of the following phenomena contributes significantly to the reddish appearance of the sun at sunrise or sunset?

Options

A. Dispersion of light
B. Scattering of light
C. Total internal reflection of light
D. Reflection of light from the earth

Explanation

To solve the question regarding the reddish appearance of the sun at sunrise or sunset, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding the Position of the Earth and Sun**:
- At sunrise and sunset, the Earth is positioned such that the sunlight has to pass through a larger thickness of the Earth's atmosphere compared to when the sun is overhead (noon).

2. **Path of Sunlight**:
- During sunrise and sunset, the sunlight travels a longer path through the atmosphere. This increased distance causes more interaction with air molecules and particles in the atmosphere.

3. **Scattering of Light**:
- The phenomenon responsible for the reddish appearance is known as Rayleigh scattering. Shorter wavelengths of light (like violet, blue, and indigo) scatter more than longer wavelengths (like red and orange).

4. **Result of Scattering**:
- As the shorter wavelengths scatter out of the direct line of sight, the longer wavelengths (red and orange) become more prominent. This is why the sun appears reddish during these times.

5. **Conclusion**:
- Therefore, the reddish appearance of the sun at sunrise and sunset is significantly contributed to by the scattering of light, particularly the scattering of shorter wavelengths.

### Final Answer:
The phenomenon that contributes significantly to the reddish appearance of the sun at sunrise or sunset is **the scattering of light**.

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