Silhouettes forms when an opaque object is between a light source and a screen which just give you a black shadow on the screen. That is called silhouette. Light intensity is the amount of light in a certain area. Today, people measure light intensity with light meters. Who needs light intensity? Film makers do! It's for the film's lighting. Sunlight is also called as a White light. White light is made up of different colors, but we can't see them! Isaac Newton was the one that predicted about rainbows correctly! When it's rainy, and there is the Sun, the white light will travel from the sun to the raindrops in the Sky in a certain angle then it will make a rainbow! The shape of the rainbow is a circle or a rainbow arc! When whitelight passes through a Prism, it bends! It's called refraction. When light is bend, it's called refraction. Lux it the unit for light intensity!