Rainbows are formed by

Options

A. reflection and diffraction
B. refraction and scattering
C. dispersion and total internal reflection
D. interference only

Answer

**Step-by-Step Solution:**

1. **Understanding the Formation of Rainbows:**
Rainbows are optical phenomena that occur when light interacts with water droplets in the atmosphere.

2. **Role of Water Droplets:**
Tiny droplets of water suspended in the air act as prisms. When sunlight enters these droplets, it undergoes various processes that lead to the formation of a rainbow.

3. **Refraction of Light:**
As sunlight (which is composed of different colors) enters a water droplet, it bends or refracts due to the change in medium from air to water. This bending of light causes the different colors to spread out, a process known as dispersion.

4. **Dispersion of Light:**
Dispersion is the phenomenon where white light is separated into its constituent colors (red, orange, yellow, green, blue, indigo, violet) due to varying degrees of bending for different wavelengths of light.

5. **Total Internal Reflection:**
After dispersion, the light hits the back surface of the droplet. If the angle of incidence is greater than the critical angle, total internal reflection occurs. This means the light reflects back into the droplet instead of refracting out.

6. **Emergence of Light:**
The reflected light then exits the droplet, and as it does so, it refracts again. This second refraction further separates the colors, enhancing the visibility of the rainbow.

7. **Conclusion:**
Therefore, rainbows are formed due to the combined effects of dispersion and total internal reflection of light in water droplets.

**Final Answer:**
Rainbows are formed by the processes of dispersion and total internal reflection of light in tiny water droplets suspended in the atmosphere.

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