Newton’s theory of light important because Sir Isaac newton, one of the greatest scientist of all time, developed a fundamentals theory about light that is known as the Corpuscular Theory.
According to this theory, light consists of corpuscles which ate a stream of discrete, tiny, light and elastic particles that travel in perfectly straight lines in all directions. Every luminous source like the sun, or a lamp, or a cradle, emits these corpuscles. According to this theory, we are able to see different colors because of the difference in sizes of these corpuscles.
The theory also stated that when corpuscles hit a surface. Each particle is reflected and that when light travels from air into water, It will increase in speed.
Newton’s corpuscles theory was important, even though he was wrong on some points. After hundred years of existence it later gave way to the more popular Christian Huygens’ wave front theory.