Light is a wave-shaped energy elekromagnetik visible wavelengths approximately 380 – 790 nm. In physics, light is electromagnetic radiation with a wavelength, whether visible or not.
Light is a particle called the photon packet.
Both of the above definition is shown simultaneously so that the light is called the "wave-particle duality". Packets of light called the spectrum then are perceived visually by the sense of sight as the color. The study of light, known as optics, is an important research area in modern physics.
Study of light began with the advent of the era of classical optics, the study of optical quantities such as: intensity, frequency or wavelength, polarization and phases of light. The properties and interactions of light around a geometric approach to partially done such as reflection and refraction, optical properties of fisisnya and approach are: interference, diffraction, dispersion, polarization. Each study of classical optics, this is called geometrical Optics (en: geometrical optics) and physical Optics (en: physical optics).
