This page gathers the 3,177 dictionary entries belonging to the domain “Physics”, as labelled by Wiktionary. Each word leads to its full entry: definitions, etymology, pronunciation, examples. Page 21 of 32: from “path length” to “Planck”.
- path length noun The distance travelled by light in a specified context.
- path of least resistance noun The path or route by which an object can move while minimizing the amount of resistance on the object's movement.
- pavement noun A paved surface; a hard covering on the ground.
- pbar noun antiproton (pronunciation spelling of the symbol p̄)
- PDLC noun polymer dispersed liquid crystal.
- pear gauge noun A kind of gauge for measuring the exhaustion (creation of a vacuum) of an air pump receiver (airtight vessel from which air is pumped in…
- pedestal noun The measured value when no input signal is given.
- pellicle noun A thin plastic membrane used as a beam splitter or protective cover (for example, to protect a photomask).
- Peltier effect noun A thermoelectric effect which occurs when current is passed through a thermocouple causing one side of the Peltier to heat up and the other…
- pencil noun An aggregate or collection of rays of light, especially when diverging from, or converging to, a point.
- penguin diagram noun A type of unicyclic Feynman diagram in which a quark temporarily changes flavor and engages in an interaction.
- peniche noun Material inserted between a half-model, often of an airplane, and the wall of a wind tunnel.
- penny verb To circumvent the tripping of an electrical circuit breaker by the dangerous practice of inserting a coin in place of a fuse in a fuse…
- Penrose transform noun A complex analog of the Radon transform that relates massless fields on spacetime, or more precisely the space of solutions to massless…
- pentaquark noun Any of a class of subatomic particles (previously hypothetical, since detected, subject to confirmation) consisting of a group of five…
- period doubling noun A characteristic of the transition of a system or process from regular motion to chaos, in which the period of one of its parameters is…
- periodic structure noun A structure made of bays coupled through one or more coordinates.
- peritectic adj Describes the isothermal reversible reaction of a liquid phase and a solid phase to form a second solid phase during cooling
- peritectoid adj Describes the isothermal reversible reaction of multiple solid phases to form a new system of fewer solid phases during cooling.
- permanence noun The reciprocal of magnetic inductance.
- permanent magnet noun A material, or piece of such material, which retains its magnetism even when not subjected to any external magnetic fields.
- permanent wave noun A wave in a moving fluid that does not change shape or position relative to the fluid
- permeability noun A quantitative measure of the degree of magnetization of a material in the presence of an applied magnetic field (measured in newtons per…
- permeameter noun An instrument used to measure the electromagnetic permeability of a material.
- permeance noun The reciprocal of reluctance in a magnetic circuit; the analogue of conductance in an electrical circuit.
- permissivity noun permittivity
- permittance noun The power of a dielectric to permit or enhance induction.
- permittivity noun A property of a dielectric medium that determines the forces that electric charges placed in the medium exert on each other.
- permutator noun A special form of rotary converter with stationary commutator and rotating brushes, in which the exciting field is induced by the…
- permuton noun A probability measure Φ on the σ-algebra of Borel sets of the unit square [0,1]² such that Φ has uniform marginals (that is, Φ ([α, β] ×…
- perpetual motion noun The motion of some hypothetical device that continues forever with no external input of energy, in violation of the laws of thermodynamics.
- perpetual motion machine noun A hypothetical, pseudoscientific device that exhibits perpetual motion, especially one that does useful work with no input of energy.
- perturbation noun Variation in an orbit due to the influence of external bodies.
- perturber noun A source of perturbation.
- PeVatron noun An astrophysical particle accelerator capable of energizing cosmic rays to PeV (“peta-electron-volt”) power levels.
- phantom energy noun A category of dark energy, where dark energy is not fixed in amount nor in density, and continuously increases over time.
- phase noun Any one point or portion in a recurring series of changes, as in the changes of motion of one of the particles constituting a wave or…
- phase angle noun Angular component of the vector representation of a sinusoid.
- phase diagram noun A graph, with axes representing temperature and pressure, showing the equilibrium conditions for a given substance to be a solid, liquid or…
- phase rule noun the rule which states that the number of degrees of freedom in a system at equilibrium equals the number of components minus the number of…
- phase separation noun The conversion of a single-phase system into a multiphase system; especially the separation of a solution into two immiscible liquids.
- phase space noun Given a (dynamical) system, any topological space such that every point in the space's underlying set uniquely represents a state of the…
- phase transition noun The transition between thermodynamic phases of a physical system, especially one between the solid, liquid, and gaseous phases of a…
- phenomenology noun The translation of theory into measurable or observable predictions that can be used to experimentally test it.
- phlogistic adj Pertaining to or containing phlogiston.
- phonobreather noun A non-linear wave that can transport energy in a coupled oscillator chain by means of a phase-torsion mechanism.
- phonon noun The quantum of acoustic or vibrational energy (sound), considered a discrete particle rather than a wave.
- photechy noun The ability of a radioactive substance to pass on useful properties of radiation (such as luminescence) to another substance.
- photo echo noun A form of resonance sometimes observed as a coherent pulse of light after two similar pulses have traversed a medium.
- photo-Dember effect noun The formation of a charge dipole in the vicinity of a semiconductor surface after ultrafast photogeneration of charge carriers.
- photoactivation noun The absorption of energy from a photon in raising a molecule (or chromophore) from the ground state; especially the first stage of…
- photoassociation noun The association of two atoms, under the influence of laser light, to form an excited diatomic molecule.
- photocage noun Any of several molecular species that can be activated by light; they are used especially in biochemistry to attach a molecule to a…
- photochop verb To convert, by chopping, a DC (or slowly varying AC) input signal into a higher frequency signal.
- photochronograph noun An instrument for recording very short intervals of time. The record is made by the power of a magnetic field, due to an electric signaling…
- photoconductivity noun The increase in the electrical conductivity of a material as a result of incident electromagnetic radiation.
- photocycle noun Any of several biochemical cycles, involving photoactive proteins, that take place in the retina when exposed to light
- photocyclization noun Any intramolecular photochemical process leading to a ring system by formation of one new single bond, either by a concerted process (e.g.…
- photodetachment noun The absorption of a photon and subsequent elimination of an electron from an anion to form a neutral species.
- photoelectret noun An electret produced when a source of illumination is removed from a photoconductor in an electric field
- photoelectric effect noun The emission of electrons from the surface of a material following the absorption of electromagnetic radiation.
- photoelectrochemistry noun A field of study combining photochemistry and electrochemistry that studies the interaction of light with electrochemical systems
- photoelectromagnetic effect noun The generation of an electric current in an intermetallic semiconductor in a magnetic field by the action of light.
- photofield noun Used attributively to describe a form of photoemission in which an electron in a metal is excited by a photon and subsequently tunnels out…
- photoinitiation noun The photoproduction of a radical or ion that is capable of initiating a chain reaction; used especially to initiate polymerization
- photomagnet noun Any material whose magnetic properties are changed by interaction with light
- photomagnetic adj of, or relating to the effect of light on the magnetic susceptibility of some materials, especially to the paramagnetism exhibited by some…
- photomagnetoelectric adj of, or relating to the generation of an electric current by an illuminated semiconductor in a magnetic field
- photometeor noun Any visible phenomenon in the atmosphere caused by reflection, refraction, diffraction or interference.
- photometer noun Any of several instruments used to measure various aspects of the intensity of light.
- photometry noun The measurement of various aspects of light, especially its intensity.
- photomultiplier noun A device, normally in the form of a tube, that uses a photocathode to convert photons into photoelectrons which are then amplified.
- photomultiplier tube noun A type of vacuum tube that detects electromagnetic radiation in the range from ultraviolet to infrared, including the visible spectrum, and…
- photon noun The quantum of light and other electromagnetic energy, regarded as a discrete particle having zero rest mass, no electric charge, and an…
- photon tunnelling noun The transmission of light through apertures of dimension smaller than the wavelength of the light by quantum tunnelling
- photoneutrino noun A neutrino that is produced (along with an antineutrino) when a high-energy photon collides with an electron
- photooxidation noun The loss of an electron from a photoexcited species.
- photoreduction noun The addition of an electron to a photoexcited species.
- photorelease noun The photoinduced release of one compound from another
- photoresistor noun An electronic component whose resistance is inversely proportional to the intensity of incident light.
- photostationary adj Describing a steady state reached by a photochemical reaction in which the rates of formation and disappearance of transient species are…
- photovisual adj Of certain achromatic lenses, having the same focus for the actinic and for the brightest of the visual rays.
- photovoltaic effect noun The conversion of electromagnetic radiation into electric power through absorption by a semiconducting material.
- photovoltaics noun The technology of the conversion of sunlight into electricity using semiconductors that exhibit the photovoltaic effect.
- physical quantity noun A physical property that can be measured or calculated from other physical property and expressed as the product of a numerical value and a…
- physical system noun The portion of the physical universe chosen for analysis, with everything outside the system known as the environment.
- picture tube noun In a television set, before the development of LED screens, the cathode ray tube which produced moving images on its surface.
- piezocoefficient noun A piezoelectric coefficient that quantifies the relationship between change in volume and strength of electric field
- piezoresponse noun The change in dimension of a ferromagnetic material in the presence of an electric field; the piezoelectric effect
- pigtail verb To connect wires of a circuit by means of a short additional wire.
- pigtailed adj Connected by means of a short additional wire.
- pilot wave noun A theoretical matter wave that guides the motion of point particles.
- pin noun Any of the individual connecting elements of a multipole electrical connector.
- pinch noun A magnetic compression of an electrically conducting filament.
- pinch effect noun the magnetic self-attraction of parallel electric currents having the same direction; the restriction of a flowing plasma because of this…
- pinning noun The establishment of the definite quantum state of a particle, or of the occupation number of a system of particles
- pinout noun The manner in which an electrical connector or device is wired; the list of signals that correspond to each pin or output.
- pion noun Any of three semistable mesons, having positive, negative or neutral charge, composed of up and down quarks/antiquarks.
- pionium noun an exotic atom equivalent to a hydrogen atom with the proton replaced by a pion
- Planck noun Used attributively in the names of various units, formulae etc. first devised or worked on by the German physicist Max Planck (1858–1947)…