Reflection of Light

The correct answer to the question is option 'C', which is reflection of light.

Reflection of light is the phenomenon where light waves bounce off a surface and change direction. When light from the sun or the moon encounters tiny ice crystals or water droplets in the atmosphere, it can be reflected off these particles, creating a halo or ring around the celestial body. This phenomenon is commonly known as a halo or a corona.

Explanation:

Formation of Halos:
When sunlight or moonlight passes through the atmosphere, it encounters ice crystals or water droplets suspended in the air. These particles act as tiny prisms or mirrors that can reflect and refract light. The interaction of light with these particles leads to the formation of halos.

1. Refraction of Light:
When sunlight or moonlight enters an ice crystal or a water droplet, it undergoes refraction. Refraction is the bending of light as it passes from one medium to another with different optical densities. The refraction of light causes the light waves to change direction and spread out.

2. Reflection of Light:
As the light waves continue to propagate inside the ice crystal or water droplet, they can also undergo multiple internal reflections. This reflection occurs when the light waves bounce off the inner surfaces of the particles. The reflected light waves can then exit the particle and contribute to the formation of the halo.

3. Dispersion of Light:
In addition to reflection and refraction, the ice crystals or water droplets can also cause the dispersion of light. Dispersion is the phenomenon where white light, such as sunlight, is separated into its component colors due to differences in the refractive index for different wavelengths. This dispersion can result in the appearance of colors within the halo.

4. Halo Formation:
The combination of refraction, reflection, and dispersion of light within the ice crystals or water droplets leads to the formation of a halo. The shape and characteristics of the halo depend on the size and shape of the particles in the atmosphere.

Conclusion:

In conclusion, the haloes or rings around the sun or the moon are caused by the reflection of light off ice crystals or water droplets in the atmosphere. The interaction of light with these particles leads to refraction, reflection, and dispersion, resulting in the formation of halos.