What is Light ?
Light is simply a name for a range of electromagnetic radiation that can be detected by the human eye. Light is a form of invisible energy packets known as photon which produces the sensation of sight. The object which emit light are known as sources of light or luminous object. A ray of light is a path followed by light energy in a transparent medium. A group of parallel rays of light emitted by the source of light is called beam of light.
The wave nature of light was first illustrated through experiments on diffraction and interference. Like all electromagnetic waves, light can travel through a vacuum. The speed of light in a vacuum is 299,792,458 meters per second. The transverse nature of light can be demonstrated through polarization.
The wavelength (which is related to frequency and energy) of the light determines the perceived color. The ranges of these different colors are listed in the table below. Some sources vary these ranges pretty drastically, and the boundaries of them are somewhat approximate as they blend into each other. The edges of the visible light spectrum blend into the ultraviolet and infrared levels of radiation.