EVERYDAY SCIENCE

Detailed explanation-1: -The rainbow is circular because when a raindrop bends light, the light exits the raindrop at an angle 40 to 42 degrees away from the angle it entered the raindrop and regarding full circular rainbow, But if the sun is very low in the sky, either just before sunset or just after sunrise, we can see a half circle.

Detailed explanation-2: -All rainbows are actually full circles, but most people only ever see an arc or semicircle because they are standing on the ground and the other half is cut off by the horizon. If you see a rainbow from an aeroplane, you might see the full circle.

Detailed explanation-3: -A rainbow is a meteorological and optical phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky. It takes the form of a multicoloured circular arc.

Detailed explanation-4: -Rainbows are circular because raindrops are spherical. When light from the Sun enters a raindrop it is largely reflected back inside a cone with a half-angle of 42 degrees. The reflected light is strongest along the surface of this cone where it is broken up into a spectrum of colours.

Detailed explanation-5: -The reason why a rainbow forms an arc and it does not go straight: When sunlight strikes a raindrop, the red light waves are bent at a 42 ° angle from the sun’s initial direction. Violet light waves that are shorter are only bent at a 40 ° angle.