Which of the following is not involved in Rainbow formation?

Options

A. Refraction
B. Internal reflection
C. Angular deviation
D. Dispersion

Answer

To determine which of the following is not involved in rainbow formation, we need to understand the processes that contribute to the formation of a rainbow. Here’s a step-by-step breakdown:

### Step 1: Understand the Formation of a Rainbow
A rainbow is formed when sunlight interacts with water droplets in the atmosphere. The key processes involved in this interaction are refraction, dispersion, and total internal reflection.

### Step 2: Refraction
When sunlight enters a water droplet, it bends or refracts due to the change in medium from air to water. This bending of light is the first step in rainbow formation.

### Step 3: Dispersion
As the light refracts, it also disperses into its constituent colors (red, orange, yellow, green, blue, indigo, violet). This occurs because different colors of light bend by different amounts.

### Step 4: Total Internal Reflection
After dispersion, the light reflects off the inner surface of the droplet. This reflection is known as total internal reflection, which helps to direct the light back towards the observer.

### Step 5: Final Refraction
As the light exits the droplet, it refracts again, further separating the colors and allowing them to spread out into a circular arc, which we perceive as a rainbow.

### Step 6: Identify the Incorrect Option
Now, we need to identify which option is not involved in the rainbow formation. The processes we identified (refraction, dispersion, total internal reflection) are all involved. However, if an option mentions "angular deviation," it is not a process involved in the formation of a rainbow itself. It may describe the result of the light's path but is not a fundamental process like the others.

### Conclusion
The correct answer to the question is that "angular deviation" is not involved in the formation of a rainbow.