A RAINBOW IS CAUSED BY REFLECTION, REFRACTION AND DISPERSION OF LIGHT RAYS IN WATER DROPLETS RESULTING IN THE APPEARANCE OF SPECTRUMS OF LIGHT IN AN ARC-LIKE SHAPE IN THE SKY. A RAINBOW CONSIST OF 7 VISIBLE COLOURS (ROYGBIV).
THIS METEOROLOGICAL PHENOMENON APPEARS IN THE SECTION OF THE SKY OPPOSITE THE SUN.
STEPS OF RAINBOW FORMATION
- LIGHT FROM THE SUN STRIKES RAINDROP AT A CERTAIN ANGLE. THE SUN MUST BE POSITIONED AT A VERY LOW ANGLE (IN THE MORNING OR IN THE EVENING) BEFORE A RAINBOW CAN BE SEEN.
- SOME OF THE LIGHT IS REFLECTED, WHILE THE REST OF THE LIGHT RAYS ARE REFRACTED (THE LIGHT RAY BENDS AFTER HITTING WATER TO AIR INTERFACE)
- WHITE LIGHT FROM THE SUN SPLITS INTO SPECTRUMS OF COLOURS. THIS IS CALLED DISPERSION.
- LIGHT IS REFLECTED AT THE REAR OF RAINDROPS(THE WATER TO AIR BOUNDARY). A RAINBOW WILL ONLY BE FORMED IF THE ANGLE OF INCIDENCE IS GREATER THAN THE CRITICAL ANGLE.
- THE LIGHT RAY IS REFRACTED AGAIN AS IT LEAVES RAINDRO. AT THIS POINT, THE SPEED INCREASES BECAUSE THE LIGHT IS MOVING FROM A DENSER MEDIUM(WATER) TO A LESS DENSE MEDIUM (AIR).
- THE SPECTRUM OF COLOURS ARE FURTHER DISPERSED, AND THERE'S INCREASE IN SEPERATION OF THE COMPONENT COLOURS OF THE LIGHT RAYS AND THIS BRINGS ABOUT THE LARGE APPEARANCE OF THE COLOURS ON THE SKY.
PS; ROYGBIV IS AN ACRONYM FOR RED,ORANGE,YELLOW,GREEN,BLUE,INDIGO, AND VIOLET.
PHOTO CREDIT;https://www.gettyimages.com/photos/rainbow