Physics
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HyperPhysics Concepts
"This site was honored because of its comprehensive coverage of most of physics, the creative use of multimedia and linking, and the impact it has had on students worldwide. Online tutorials cover a wide range of physics topics, including modern physics and astronomy. Material is organized through extensive concept maps." HyperPhysics is an exploration environment for concepts in physics which employs concept maps and other linking strategies to facilitate smooth navigation. For the most part, it is laid out in small segments or "cards", true to its original development in HyperCard.
Quantum electrodynamics ( QED ) is the relativistic quantum field theory of electrodynamics . In essence, it describes how light and matter interact and is the first theory where full agreement between quantum mechanics and special relativity is achieved. QED mathematically describes all phenomena involving electrically charged particles interacting by means of exchange of photons and represents the quantum counterpart of classical electrodynamics giving a complete account of matter and light interaction.
Quantum electrodynamics - Wikipedia, the free encyclopedia
In theoretical physics , the renormalization group (RG) refers to a mathematical apparatus that allows systematic investigation of the changes of a physical system as viewed at different distance scales . In particle physics, it reflects the changes in the underlying force laws (codified in a quantum field theory ) as the energy scale at which physical processes occur varies, energy/momentum and resolution distance scales being effectively conjugate under the uncertainty principle (cf. Compton wavelength ). A change in scale is called a " scale transformation ". The renormalization group is intimately related to "scale invariance" and "conformal invariance", symmetries in which a system appears the same at all scales (so-called self-similarity ). (However, note that scale transformations are included in conformal transformations , in general: the latter including additional symmetry generators associated with special conformal transformations .)
Renormalization group - Wikipedia, the free encyclopedia
Compton scattering - Wikipedia, the free encyclopedia
In physics , Compton scattering is a type of scattering that X-rays and gamma rays (both photons with different energy ranges) undergo in matter. The inelastic scattering of photons in matter results in a decrease in energy (increase in wavelength ) of an X-ray or gamma ray photon , called the Compton effect . Part of the energy of the X/gamma ray is transferred to a scattering electron, which recoils and is ejected from its atom (which becomes ionized ), and the rest of the energy is taken by the scattered, "degraded" photon.
Photoelectric effect - Wikipedia, the free encyclopedia
In the photoelectric effect , electrons are emitted from matter (metals and non-metallic solids, liquids or gases ) as a consequence of their absorption of energy from electromagnetic radiation of very short wavelength , such as visible or ultraviolet radiation . Electrons emitted in this manner may be referred to as photoelectrons. [ 1 ] [ 2 ] First observed by Heinrich Hertz in 1887, [ 2 ] [ 3 ] the phenomenon is also known as the Hertz effect, [ 4 ] [ 5 ] although the latter term has fallen out of general use. Hertz observed and then showed that electrodes illuminated with ultraviolet light create electric sparks more easily. The photoelectric effect requires photons with energies from a few electronvolts to over 1 MeV in high atomic number elements .Pair production refers to the creation of an elementary particle and its antiparticle , usually when a photon (or another neutral boson ) interacts with a nucleus. For example an electron and its antiparticle, the positron, may be created. This is allowed, provided there is enough energy available to create the pair – at least the total rest mass energy of the two particles – and that the situation allows both energy and momentum to be conserved. Other pairs produced could be a muon and anti-muon or a tau and anti-tau. However all other conserved quantum numbers ( angular momentum , electric charge , lepton number) of the produced particles must sum to zero – thus the created particles shall have opposite values of each other.
Pair production - Wikipedia, the free encyclopedia
Fundamental Force
In particle physics , fundamental interactions (sometimes called interactive forces or fundamental forces ) are the ways that elementary particles interact with one another. An interaction is fundamental when it cannot be described in terms of other interactions. The four known fundamental interactions, all of which are non-contact forces , are electromagnetism , strong interaction , weak interaction (also known as "strong nuclear force" and "weak nuclear force" respectively) and gravitation .
This is a list of the different types of particles, known and hypothesized. For a chronological listing of subatomic particles by discovery date, see Timeline of particle discoveries . This is a list of the different types of particles found or believed to exist in the whole of the universe . For individual lists of the different particles, see the individual pages given below. [ edit ] Elementary particles Elementary particles are particles with no measurable internal structure; that is, they are not composed of other particles.
List of particles - Wikipedia, the free encyclopedia