Explain the formation of rainbow in the sky with the help of a diagram. List the three phenomena of light involved. Which colour – violet or red appears at top of the rainbow? B. What is the difference in colours of the sun observed during sunrise/sunset and noon? Give explanation for each.

A. Formation of Rainbow: A rainbow is formed when light is refracted, reflected, and dispersed in water droplets in the atmosphere. The three main phenomena of light involved in the formation of a rainbow are:

Refraction: As sunlight enters a raindrop, it is refracted (bent) at the surface of the raindrop.
Reflection: The light is then internally reflected off the inside surface of the raindrop.
Dispersion: The internal reflection causes the light to be dispersed into its individual colors due to the different wavelengths of each color. This separation of colors is known as dispersion.

The violet color appears at the bottom of the rainbow, and the red color appears at the top.

B. Difference in Colors of the Sun:

Sunrise/Sunset: (Colors) During sunrise and sunset, the sun appears reddish or orange.
Explanation: When the sun is near the horizon, sunlight has to pass through a thicker layer of the Earth’s atmosphere. The atmosphere scatters shorter wavelengths (blue and violet light) more than longer wavelengths (red and orange light). As a result, the shorter wavelengths are scattered out of our line of sight, leaving the longer wavelengths to dominate the sky, creating the warm colors observed during sunrise and sunset.

Noon: (Colors): The sun appears white or slightly yellow at noon.
Explanation: When the sun is directly overhead, sunlight has to pass through a smaller portion of the Earth’s atmosphere. There is less atmospheric scattering, and the sunlight reaches us with its full spectrum of colors. As a result, the sun appears white or slightly yellow at noon when observed from the Earth’s surface.

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