RAINBOW

Series of concentric, coloured arc that may be see when light from a distant soure-usually the sun-falls on a collection of water droups such as in rain, spray or fog. The colered ray of the rain bow are caused by the refraction and total intanel raflection of light ray that enters the drop,each colour beeing bend through slightly different angle.Hence yhe different colours are spread upon emerging from the droup.The most brilliant and most common rainbow is the so-called rainbow,which results from light that emerges from the drop after one internal reflection.The colour of the arc (from outside to inside) red,orange,yellow,green,blue,indigo and violet. Occationaly a less-intese secotary bow may be observed;it has its colour sequence reversed.