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emit: [verb] to throw or give off or out. to send out : eject.
5 days ago · EMIT LIGHT definition | Meaning, pronunciation, translations and examples
Emit definition: to send forth (liquid, light, heat, sound, particles, etc.); discharge.. See examples of EMIT used in a sentence.
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- Overview
- Quantum electrodynamics
That materials, when heated in flames or put in electrical discharges, emit light at well-defined and characteristic frequencies was known by the mid-19th century. The study of the emission and absorption spectra of atoms was crucial to the development of a successful theory of atomic structure. Attempts to describe the origin of the emission and a...
The foundations of a quantum mechanical theory of light and its interactions with matter were developed in the late 1920s and ’30s by Paul Dirac, Werner Heisenberg, Pascual Jordan, Wolfgang Pauli, and others. The fully developed theory, called quantum electrodynamics (QED), is credited to the independent work of Richard Feynman, Julian S. Schwinger, and Tomonaga Shin’ichirō. QED describes the interactions of electromagnetic radiation with charged particles and the interactions of charged particles with one another. The electric and magnetic fields described in Maxwell’s equations are quantized, and photons appear as excitations of those quantized fields. In QED, photons serve as carriers of electric and magnetic forces. For example, two identical charged particles electrically repel one another because they are exchanging what are called virtual photons. (Virtual photons cannot be directly detected; their existence violates the conservation laws of energy and momentum.) Photons can also be freely emitted by charged particles, in which case they are detectable as light. Though the mathematical complexities of QED are formidable, it is a highly successful theory that has now withstood decades of precise experimental tests. It is considered the prototype field theory in physics; great efforts have gone into adapting its core concepts and calculational approaches to the description of other fundamental forces in nature (see unified field theory).
QED provides a theoretical framework for processes involving the transformations of matter into photons and photons into matter. In pair creation, a photon interacting with an atomic nucleus (to conserve momentum) disappears, and its energy is converted into an electron and a positron (a particle-antiparticle pair). In pair annihilation, an electron-positron pair disappears, and two high-energy photons are created. These processes are of central importance in cosmology—once again demonstrating that light is a primary component of the physical universe.
EMIT meaning: 1. to send out a beam, noise, smell, or gas: 2. to send out a beam, noise, smell, or gas: 3. to…. Learn more.
to send out something such as light, heat, sound, gas, etc. The metal container began to emit a clicking sound. Sulfur gases were emitted by the volcano.
1 day ago · verb Word forms: emits, emitting, emitted (transitive) 1. to give or send forth; discharge. the pipe emitted a stream of water. 2. to give voice to; utter. she emitted a shrill scream. 3. physics. to give off ( radiation or particles )
