Q4. For a rainbow to be formed, do rain is always necessary. Give reasons. Ans.
No,not necessarily. There are many atmospheric phenomena that will produce colours in the sky apart from rainbows and it doesn't have to be raining near you for a rainbow to form, but there has to be rain to form such rainbows. A rainbow will only form in front of you when the sun is directly behind you. If you can see the colours near the sun, then you are not looking at a rainbow. But all it requires is suspended water droplets(spheres).
The splashing of water at the base of a waterfall caused a mist of water in the air that often results in the formation of rainbows. A backyard water sprinkler is another common source of a rainbow. Bright sunlight, suspended droplets of water and the proper angle of sighting are the three necessary components for viewing one of nature's most splendid masterpieces.
To view a rainbow, your back must be to the sun as you look at an approximately 40 degree angle above the ground into a region of the atmosphere with suspended droplets of water or even a light mist. Each individual droplet of water acts as a tiny prism that both disperses the light and reflects it back to your eye. As you sight into the sky, wavelengths of light associated with a specific color arrive at your eye from the collection of droplets. The net effect of the vast array of droplets is that a circular arc of ROYGBIV is seen across the sky. “Internal Reflection” “Angle Of Deviation”
“Formation of Rainbow”
The circle (or half-circle) results because there are a collection of suspended droplets in the atmosphere that are capable concentrating the dispersed light at angles of deviation of 40-42 degrees relative to the original path of light from the sun. These droplets actually form a circular arc, with each droplet within the arc dispersing light and reflecting it back towards the observer. Every droplet within...
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