luz

Luz is the term used in Spanish and Portuguese to refer to light, the visible portion of the electromagnetic spectrum along with related electromagnetic radiation. In physics, light describes electromagnetic waves that interact with matter and can be detected by the human eye. Light encompasses a range of wavelengths, with visible light spanning roughly 380 to 750 nanometers, and it also includes nearby infrared and ultraviolet radiation.

Light travels as waves through space at approximately 299,792 kilometers per second in a vacuum, a speed that can be reduced when light passes through materials with a higher refractive index. It also exhibits particle-like properties, consisting of photons, which are quanta of energy with energy proportional to frequency (E = hf). The color of light depends on its wavelength, while its brightness relates to its intensity. Common light–matter interactions include reflection, refraction, absorption, scattering, and diffraction.

Common sources of luz include natural light, such as sunlight and fire, and artificial light, produced by lamps, LEDs, and lasers. In everyday use, photometric quantities like luminance and illuminance describe how light is perceived by the human eye, whereas radiometric quantities measure its physical energy.

Luz underpins vision, imaging, and many technologies. It enables photography, displays, fiber-optic communications, and medical procedures, while daylight and artificial lighting influence design, energy use, and human activity. The study of light has a long scientific history, from early optical experiments to the development of Maxwell’s equations and quantum theories that explain its dual wave–particle nature.