The Standard Electrical Dictionary Part 131

A battery is connected in quant.i.ty when the cells are all in parallel.

It is the arrangement giving the largest current through a very small external resistance.

The term is now virtually obsolete (Daniell); "in surface," "in parallel," or "in multiple arc" is used.

Quant.i.ty, Electric.

Electricity may be measured as if it were a compressible gas, by determining the potential it produces when stored in a defined recipient. In this way the conception of a species of quant.i.ty is reached. It is also measured as the quant.i.ty of current pa.s.sed by a conductor.

Thus a body whose surface is more or less highly charged with electricity, is said to hold a greater or less quant.i.ty of electricity.

It may be defined in electrostatic or electro-magnetic terms. (See Quant.i.ty, Electrostatic--Quant.i.ty, Electro-magnetic.)

445 STANDARD ELECTRICAL DICTIONARY.

Quant.i.ty.

Electro-magnetic. Quant.i.ty is determined electro-magnetically by the measurement of current intensity for a second of time: its dimensions are therefore given by multiplying intensity or current strength by time. The dimensions of intensity are ( (M^.5) * (L^.5) ) / T therefore the dimensions of electro-magnetic quant.i.ty are ( ( (M^.5) * (L^.5) ) / T ) * T = ( (M^.5) * (L^.5) )

Quant.i.ty, Electro-magnetic, Practical Unit of.

The quant.i.ty of electricity pa.s.sed by a unit current in unit time; the quant.i.ty pa.s.sed by one ampere in one second; the coulomb.

It is equal to 3E9 electrostatic absolute units of quant.i.ty and to 0.1 of the electro- magnetic absolute unit of quant.i.ty.

One coulomb is represented by the deposit of .00111815 gram, or .017253 grain of silver, .00032959 gram, or .005804 grain of copper, .0003392 gram, or .005232 grain of zinc.

If water is decomposed by a current each coulomb is represented by the cubic centimeters of the mixed gases (hydrogen and oxygen) given by the following formula.

( 0.1738 * 76 * (273 + C? ) ) / ( h * 273 ) in which C? is the temperature of the mixed gases in degree centigrade and h is the pressure in centimeters of mercury column; or by ( 0.01058 * 30 (491 + F? - 32) ) / (h * 491 ) for degrees Fahrenheit and inches of barometer.

[Transcriber's note: 6.24150962915265E18 electrons is one coulomb.]

Quant.i.ty, Electrostatic.

Quant.i.ty is determined electro-statically by the repulsion a charge of given quant.i.ty exercises upon an identical charge at a known distance.

The force evidently varies with the product of the two quant.i.ties, and by the law of radiant forces also inversely with the square of the distance. The dimensions given by these considerations is Q * Q/(L*L).

This is the force of repulsion. The dimensions of a force are (M * L) /(T^2). Equating these two expressions we have: (Q^2)/(L^2) = (M*L)/(T^2) or Q = ((M^.5)*(L^1.5)) / T which are the dimensions of electrostatic quant.i.ty.

Quant.i.ty, Meter.

An electric meter for determining the quant.i.ty of electricity which pa.s.ses through it, expressible in coulombs or ampere hours. All commercial meters are quant.i.ty meters.

446 STANDARD ELECTRICAL DICTIONARY.

Quartz.

A mineral, silica, SiO2. It has recently been used by C. V. Boys and since by others in the making of filaments for torsion suspensions. The mineral is melted, while attached to an arrow or other projectile. It is touched to another piece of quartz or some substance to which it adheres and the arrow is fired off from the bow. A very fine filament of surpa.s.singly good qualities for galvanometer suspension filaments is produced.

As a dielectric it is remarkable in possessing but one-ninth the residual capacity of gla.s.s.

Quicking.

The amalgamating of a surface of a metallic object before silver plating. It secures better adhesion of the deposit. It is executed by dipping the article into a solution of a salt of mercury. A solution of mercuric nitrate 1 part, in water 100 parts, both by weight, is used.

R.

(a) Abbreviation and symbol for Reamur, as 10? R., meaning 10? by the Reamur thermometer. (See Reamur Scale.)

(b) Symbol for resistance, as in the expression of Ohm's Law C=E/R.

(rho, Greek r) Symbol for specific resistance.

Racing of Motors.

The rapid acceleration of speed of a motor when the load upon it is removed. It is quickly checked by counter-electro-motive force. (See Motor, Electric.)

Radian.

The angle whose arc is equal in length to the radius; the unit angle.

Radiant Energy.

Energy, generally existing in the luminiferous ether, kinetic and exercised in wave transmission, and rendered sensible by conversion of its energy into some other form of energy, such as thermal energy.

If the ether waves are sufficiently short and not too short, they directly affect the optic nerve and are known as light waves; they may be so short as to be inappreciable by the eye, yet possess the power of determining chemical change, when they are known as actinic waves; they may be also so long as to be inappreciable by the eye, when they may be heat-producing waves, or obscure waves.

Other forms of energy may be radiant, as sound energy dispersed by the air, and gravitational energy, whose connection with the ether has not yet been demonstrated.

Radiation.

The traveling or motion of ether waves through s.p.a.ce.

[Transcriber's note: The modern term corresponding to this definition is photons. The modern concept of radiation also includes particles-- neutrons, protons, alpha (helium) and beta (electrons) rays and other exotic items.]

Radicals.

A portion of a molecule, possessing a free bond and hence free to combine directly. A radical never can exist alone, but is only hypothetical. An atom is a simple radical, an unsaturated group of atoms is a compound radical.

447 STANDARD ELECTRICAL DICTIONARY.

Radiometer.

An instrument consisting of four vanes poised on an axis so as to be free to rotate, and contained in a sealed gla.s.s vessel almost perfectly exhausted. The vanes of mica are blackened on one side.

On exposure to light or a source of heat (ether waves) the vanes rotate.

The rotation is due to the beating back and forth of air molecules from the surface of the vanes to the inner surface of the gla.s.s globe.