The correct Answer is Diffraction
Explanation
The formation of a rainbow is a natural phenomenon resulting from the interaction of sunlight with water droplets in the atmosphere. This process involves several optical principles.Statement-wise Analysis
Refraction
- Correct. When sunlight enters a water droplet, it bends or refracts as it passes from air to water. This is the initial bending of light. Similarly, when light exits the water droplet back into the air, it refracts again. Therefore, refraction is involved in the formation of a rainbow.
Internal reflection
- Correct. After entering the water droplet and undergoing refraction, the light ray strikes the back inner surface of the droplet. At this interface, the light undergoes total internal reflection, bouncing back within the droplet. This internal reflection is crucial for the light to be directed back towards the observer.
Diffraction
- Incorrect. Diffraction is the bending of light waves as they pass around obstacles or through small openings. While diffraction can occur with light, it is not a primary or significant phenomenon involved in the formation of a rainbow's characteristic colors and arc. The primary mechanisms are refraction, dispersion, and internal reflection.
Dispersion
- Correct. Dispersion is the phenomenon where white light splits into its constituent colors (spectrum) when passing through a medium, due to different wavelengths (colors) traveling at different speeds and thus refracting at slightly different angles. In a water droplet, dispersion causes the white sunlight to separate into its various colors, which are then observed as the rainbow.