भौतिक विज्ञान की पारिभाषिक शब्दावली
(abscissa) किसी ग्राफ पर किसी बिन्दु की Y-अक्ष से लम्बवत दूरी; इसे X-निर्देशांक भी कहते हैं। ===परम विचलन=== (absolute deviation) परम त्रुटि (absolute error) किसी राशि के वास्तविक मान एवं मापे गये मान के बीच का अन्तर परम शून्य (absolute zero) वह ताप जिस पर ' वस्तु के अणुओं की गतिज उर्जा न्यूनतम हो जाती है; शून्य डिग्री केल्विन या -273.16 डिग्री सेल्सियस अवशोषण वर्णक्रम (absorption spectrum) A continuous spectrum interrupted by dark lines or bands that are characteristic of the medium through which the radiation has passed. त्वरण (acceleration) वेग में परिवर्तन की दर (acceptor) एक ऐसा तत्त्व जिसके प्रत्येक परमाणु के संयोजी कक्ष में इलेक्ट्रोनों की संख्या ३ हो जिससे क्रिस्टल के जालक निर्माण में अर्ध्दचालक क्रिस्टल इलेक्ट्रोनों "कोटर" उपलब्ध्द कराता है। An element with three valence electrons per atom which when added to a semiconductor crystal provides electron "holes" in the lattice structure of the crystal. शुद्धि (accuracy) किसी विशिष्ट भौतिक राशि के मापे गए मान की ग्राह्य मान से निकटता Closeness of a measurement to the accepted value for a specific physical quantity; expressed in terms of error. ध्वनिकी (Acoustics) ध्वनिकी चिरसम्मत यांत्रिकी की वह शाखा जिसके अंतर्गत श्रव्य ध्वनि, अवश्रव्य तरंगों तथा पराश्रव्य तरंगों (ठोस, द्रव व गैस में संचरित होने वाली सभी यांत्रिक तरंगों ) का अध्ययन किया जाता है Acoustics is the branch of classical mechanics concerned with the study of sound, ultrasound and infrasound (all mechanical waves in gases, liquids, and solids)। आसंजक (adhesion) दो अलग-अलग प्रकार के अणुओं के मध्य लगने वाला आकर्षण बल The force of attraction between unlike molecules. रुद्धोष्म प्रक्रम (adiabatic process) A thermal process in which no heat is added to or removed from a system. कृषि-भौतिकी (agro physics) Agrophysics is a new branch of science bordering on physics and agronomy अल्फा कण (alpha particle) A helium-4 nucleus, especially when emitted from the nucleus of a radioactive atom. प्रत्यावर्ती धारा (alternating current) An electric current that has one direction during one part of a generating cycle and the opposite direction during the remainder of the cycle. धारामापी (ammeter) An electric meter designed to measure current. एम्पीयर (ampere) The unit of electric current; one coulomb per second. आवर्धक (amplifier) A device consisting of one or more vacuum tubes (or transistors) and associated circuits, used to increase the strength of a signal. आयाम (amplitude) The maximum displacement of a vibrating particle from its equilibrium position. आपतन कोण (angle of incidence) The angle between the incident ray and the normal drawn to the point of incidence. परावर्तन कोण (angle of reflection) The angle between the reflected ray and the normal drawn to the point of incidence. अपवर्तन कोण (angle of refraction) The angle between the refracted ray and the normal drawn to the point of refraction. आंग्स्ट्राम (Angstrom) A unit of linear measure equal to 10–10 m. कोणीय त्वरण (angular acceleration) The time rate of change of angular velocity. कोणीय आघात (angular impulse) The product of a torque and the time interval during which it acts. कोणीय संवेग (angular momentum) The product of the rotational inertia of a body and its angular velocity. कोणीय वेग (angular velocity) The time rate of change of angular displacement. धनाग्र (anode) -1 The positive electrode of an electric cell. (2) (antimatter) A substance composed of antiparticles. प्रति-कण (antiparticle) A counterpart of a subatomic particle having opposite properties (except for equal mass)। द्वारक (aperture) Any opening through which radiation may pass. The diameter of an opening that admits light to a lens or आभासी शक्ति (apparent power) The product of the effective values of alternating voltage and current. (arc tangent) The inverse function to the tangent. Symbol: arctan or tan-l. Interpretation: "An angle whose tangent is (armature) A coil of wire formed around an iron or steel core that rotates in the magnetic field of a generator or motor. परमाणु (atom) The smallest particle of an element that can exist either alone or in combination with other atoms of the same or other elements. परमाणविय द्रव्यमान इकाई (atomic mass unit) One-twelfth of the mass of carbon-12, or 1.6605655 x 10–27 kg. परमाणु क्रमांक (atomic number) The number of protons in the nucleus of an atom. परमाणु भार (atomic weight) The weighted average of the atomic masses of an element's isotopes based on their relative abundance. श्रव्य संकेत (audio signal) The alternating voltage proportional to the sound pressure produced in an electric circuit. माध्य वेग (average velocity) Total displacement divided by elapsed time. (back emf) An induced emf in the armature of a motor that opposes the applied voltage. अस्त्र-विज्ञान (Ballistics) (band spectrum) An emission spectrum consisting of fluted bands of color. The spectrum of a substance in the molecular state. दाबमापी (barometer) A device used to measure the pressure of the atmosphere. (baryon) A subatomic particle with a large rest mass, e.g., the proton. मूल समीकरण (basic equation) An equation that relates the unknown quantity with known quantities in a problem. वैद्युत स्थितिकी का आधरभूत नियम (basic law of electrostatics) Similarly charged objects repel each other. Oppositely charged objects attract each other. किरण-पुंज (beam) Several parallel rays of light considered collectively. स्पन्दन (beat) The interference effect resulting from the superposition of two waves of slightly different frequencies propagating in the same direction. The amplitude of the resultant wave varies with time. बेक्वेरल (becquerel) The rate of radioactivity equal to one disintegration per second. बीटा कण (beta particle) An electron emitted from the nucleus of a radioactive atom. बीटाट्रान (betatron) A device that accelerates electrons by means of the transformer principle . (bevatron) A high-energy synchrotron. बंधक ऊर्जा (binding energy) Energy that must be applied to a nucleus to break it up. क्वथनांक (boiling point) The at which the vapor pressure of a liquid equals the pressure of the atmosphere. बोसॉन (boson) A subatomic particle with zero charge and rest mass, e.g., the photon. बायल का नियम (Boyle's law) The volume of a dry gas varies inversely with the pressure exerted upon it, provided the temperature is constant. (breeder reactor) A nuclear reactor in which a fissionable material is produced at a greater rate than the fuel is consumed. ब्राउनी गति (Brownian movement) The irregular and random movement of small particles suspended in a fluid, known to be a consequence of the thermal motion of fluid molecules. (bubble chamber) Instrument used for making the paths of ionizing particles visible as a trail of tiny bubbles in a liquid. कैलरी (calorie) The quantity of heat equal to 4.19 joules. उष्मामापी (calorimeter) A heat-measuring device consisting of nested metal cups separated by an air space. कैंडल (candle) The unit of luminous intensity of a light source. धारिता (capacitance) The ratio of the charge on either plate of a capacitor to the potential difference between the plates. capacitive reactance. Reactance in an a-c circuit containing capacitance which causes a lagging voltage. संधारित्र (capacitor) A combination of conducting plates separated by layers of a dielectric that is used to store an electric charge. सूक्ष्म नलिका (capillarity) The elevation or depression of liquids in small-diameter tubes. ऋणाग्र (cathode) -1 The negative electrode of an electric cell. (2) कैथोड किरणें (cathode rays) Particles emanating from a cathode; electrons. सेल्सियस पैमाना (Celsius scale) The temperature scale using the ice point as 0o and the steam point as 100o, with 100 equal divisions, or degrees, between; formerly the centigrade scale. वक्रता केन