| 释义 |
Faraday|ˈfærədeɪ|
The name of Michael Faraday (1791–1867), English scientist, used:
1. attrib. or in the possessive to designate certain phenomena observed, apparatus invented, and principles enunciated by him.
Faraday cage, an earthed metal screen surrounding a piece of equipment to protect it from external electrostatic interference; Faraday's constant = Faraday 2; Faraday('s) dark space, in a discharge tube the dark space observed between the positive column and the negative glow when the pressure is moderately low; also called the second dark space; Faraday('s) disc, a metal disc in which an e.m.f. is induced when it is made to rotate in a magnetic field parallel to the axis of rotation; Faraday effect, the rotation of the plane of polarization of light or other electromagnetic waves when transmitted through certain substances in a magnetic field that has a component parallel to the direction of transmission; Faraday('s) ice-pail experiment, an experiment used to demonstrate certain principles of electrostatic induction; Faraday's law, any of two or three laws; (a) when the magnetic flux linking a circuit changes, an e.m.f. is induced in the circuit proportional to the rate of change of the flux linkage (the law of induction); (b) the amount of any substance deposited or liberated during electrolysis is proportional to (i) the quantity of charge passed and (ii) the equivalent weight of the substance (the law(s) of electrolysis); (quot. 1850 refers to a different phenomenon); Faraday's line, a line of force of a magnetic field; Faraday tube, a tube of force of an electrostatic field, defined so that one tube arises from a unit charge.
1916G. Kapp Princ. Electr. Engin. I. vii. 103 All the transforming apparatus is in a building which is a huge Faraday cage... If the building should be struck by lightning this would momentarily acquire a high potential, but nothing inside it would be damaged. 1955A. Huxley Let. 27 Aug. (1969) 761 Harry, the Dutch sculptor,..goes into trances in the Faraday cages. 1971Physics Bull. Jan. 46/2 Ions leave the oscillator through a rectangular slot along the cathode and parallel to the wires and are collected in a Faraday cage.
1931Page & Adams Princ. Electr. vi. 201 As the atomic weight of hydrogen is 1·008 and its valence is unity, F, called Faraday's constant, is the number of coulombs required to liberate 1·008 grams of hydrogen.
1893T. O'C. Sloane Stand. Electr. Dict. 249 Faraday's Dark Space, a non⁓luminous space between the negative and positive glows, produced in an incompletely exhausted tube through which a static discharge..is produced. 1958C. G. Wilson Electr. & Magn. xii. 365 At a pressure of 10—2 mm. Hg. or less, the Faraday Dark Space and Negative Glow disappear and the Crooke's [sic] Dark Space almost fills the tube.
1886J. A. Fleming Short Lect. Electr. Artisans ii. 36 (caption) Faraday's Disk Induction Machine. 1962Corson & Lorrain Introd. Electromagn. Fields 530 Consider the Faraday disk or, as it is also called, the homo⁓polar generator.
1889O. Lodge Mod. Views Electr. xv. 278 The only substance in which the Faraday effect is large, is iron. 1966McGraw-Hill Encycl. Sci. & Technol. V. 181/1 The Faraday effect is particularly simple in substances having sharp absorption lines, that is, in gases and in certain crystals.
1888A. Gray Absol. Measurem. Electr. & Magn. I. i. 24 The results of Faraday's ice-pail experiments..are direct consequences of the following general proposition regarding closed conductors. 1953E. R. Peck Electr. & Magn. i. 35 In the Faraday ice-pail experiment, a charged metal ball is suspended by an insulating string inside a closed metal pail which is initially uncharged and is insulated except for a wire connecting it to an electroscope indicating the potential of the pail.
1850Phil. Mag. 3rd Ser. XXXVII. 245 Faraday's law..may be illustrated by some very curious although extremely simple experiments. 1881Jrnl. Chem. Soc. XXXIX. 286 The more experimental methods were refined, the more completely were the exactness and generality of Faraday's law [of electrolysis] confirmed. 1886J. A. Fleming Short Lect. Electr. Artisans ii. 31 We are able to group under one law all the effects so far described, and the expression of this is called Faraday's law of Induction. 1904R. A. Lehfeldt Electro-chem. I. i. 3 Faraday's two laws may be conveniently summed up in one statement..96600 coulombs are required for the deposition of one gram equivalent of any substance. 1954W. E. Rogers Introd. Electr. Fields xi. 307 The interrelations of a circuit with its magnetic flux are investigated most easily by relating the induced emf to the currents which produce the flux, rather than by using Faraday's law directly.
1857Rep. Brit. Assoc. 1856 12 (heading) On a method of drawing the theoretical forms of Faraday's lines of force without calculation. 1911Encycl. Brit. XVII. 323/1 Faraday's lines not only show the direction of the magnetic force, but also serve to indicate its magnitude or strength in different parts of the field.
1893J. J. Thomson Recent Res. Electr. & Magn. 3 The Faraday tubes either form closed circuits or else begin and end on atoms. 1959Chambers's Encycl. XIV. 8/1 The number of Faraday tubes in unit area was called the displacement by Maxwell.
2. As a name for the quantity of electric charge required to flow to deposit or liberate one gramme-equivalent of any element during electrolysis, viz. approximately 96,490 coulombs. (Usu. with lower-case initial letter.)
1904R. A. Lehfeldt Electro-chem. I. i. 3 This fundamental quantity of electricity, which occurs constantly in all writings on electro-chemistry, is called by the Germans a ‘faraday’, a term which we in England may very well adopt. 1940S. Glasstone Physical Chem. xii. 872 One faraday of electricity liberates 16·8 liters of gas at s.t.p. 1958Hamer & Wood in Condon & Odishaw Handbk. Physics iv. ix. 140/2 The measurements of the faraday by electrochemical methods involve the measurement of the absolute current, the time, and the mass of material reacted. |