Light:

Introduction:

The region of the electromagnetic spectrum that the human eye perceives as light, or visible light, is made up of electromagnetic radiation. Typically, visible light is characterized as having wavelengths between 400 and 700 nanometers (nm), or frequencies between 750 and 420 terahertz, which fall between the longer-wavelength infrared and the shorter-wavelength ultraviolet (with shorter wavelengths).

 

Light

The term "light" in physics can be used to more broadly describe electromagnetic radiation of any wavelength, whether or not it is visible. Gamma rays, X-rays, microwaves, and radio waves are all forms of light in this sense. Intensity, propagation direction, frequency or wavelength spectrum, and polarization are the four main characteristics of light. One of the fundamental constants of nature is its speed in a vacuum, which is 299 792 458 meters per second (m/s). Similar to all other forms of electromagnetic radiation, visible light is propagated by massless elementary particles called photons, which act as both waves and particles in an electromagnetic field. Optics, also known as the science of light, is a significant topic of study in contemporary physics.

 

The Sun is the primary source of natural light on Earth. Fire has historically been a significant source of illumination for people, from prehistoric campfires to contemporary kerosene lamps. Electric illumination has largely taken the role of firelight as a result of the development of electric lights and power networks.

 

Quantum theory:

Max Planck proposed in 1900 that although light was a wave, it could only gain or lose energy in finite amounts correlated to its frequency in an effort to explain black-body radiation. These "lumps" of light energy were known as "quanta" by Planck (from a Latin word for "how much"). Albert Einstein proposed that these light quanta had a "real" existence in 1905 when using the concept of light quanta to explain the photoelectric phenomenon. In 1923, Arthur Holly Compton demonstrated that a particle-theory of X-rays, rather than a wave theory, could explain the wavelength shift observed when low intensity X-rays scattered from electrons (henceforth referred to as Compton scattering). Gilbert N. Lewis gave these light quanta particles the name photons in 1926.

 

At some point, the contemporary theory of quantum mechanics began to depict light as both a wave and a particle, as well as a phenomenon that is neither a wave nor a particle (which actually are macroscopic phenomena, such as baseballs or ocean waves). Instead, according to contemporary physics, light can sometimes be explained mathematically using a macroscopic metaphor (such as particles) and sometimes using a different macroscopic metaphor (such as water waves), but it actually cannot be properly comprehended.Physics experts have observed that electromagnetic radiation tends to behave more like a classical wave at lower frequencies and more like a classical particle at higher frequencies, but never completely loses all qualities of one or the other. This is similar to how radio waves and the X-rays involved in Compton scattering behave. It is simple to demonstrate in tests that visible light, which falls towards the middle of the frequency spectrum, can be described by either a wave model, a particle model, or occasionally both.

 

Light

In February 2018, researchers announced for the first time their finding of a novel type of light that may contain polaritons and has the potential to aid in the creation of quantum computers.