Sir Isaac Newton held the theory that light was made up from tiny particles. In 1678 Dutch physicalChristiaan Huygens, believed that light was made up of waves vibrating up and down perpendicular to the direction of the light travels, and therefore formulated a way of visualising wave propagation. This became known as 'Huygens' Principle'.
Light Theory
Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum. All light has a source. For example sunlight come from the sun. It travels 93 millions miles to reach the Earth from the Sun. Light bulbs and candles produce another kind of light. These light sources are man made. There are even some animals, such as lighting bugs, that make their own light.
Refraction
When the light ray travels from air to water, the refracted ray bends towards the normal.
Light Particles
It conceived by Einstein is called a photon.The main point of this light quantum theory is the idea that light's energy is related to its oscillation frequency.It is equal to the speed of the light divided by its wavelength.