The Theory and Practice of Absolute Measurements in Electricity and Magnetism, Parte 2

Macmillan and Company, 1893

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Página 859 - As a unit of resistance, the international ohm, which is based upon the ohm equal to 10" units of resistance of the CGS system of electromagnetic units, and is represented by the resistance offered to an unvarying electric current by a column of mercury at the temperature of melting ice, 14.4521 grams in mass, of a constant cross-sectional area and of the length of 106.3 centimetres.
Página 860 - Ampere, which is one-tenth of the unit of current of the CGS system of electromagnetic units and which is represented sufficiently well for practical use by the unvarying current which, when passed through a solution of nitrate of silver in water, in accordance with a certain specification, deposits silver at the rate of 0.001118 of a gramme per second.
Página 713 - Art. 1, it is stated that a current will be induced in a closed coil or circuit when there is a change in the number of lines of force passing through that coil or circuit.
Página 861 - ... the electromotive force that, steadily applied to a conductor whose resistance is one international ohm, will produce a current of...
Página 861 - The volt, which has the value 10s in terms of the centimetre, the gramme, and the second of time, being the electrical pressure that if steadily applied to a conductor whose resistance is one ohm will produce a current of one ampere, and which is represented by '6974 (TTFT) of the electrical pressure at a temperature of 15° C.
Página 531 - ... to that in which the pole is moved, and it plainly does not matter which we suppose held fixed and which moved. Therefore a conductor in a magnetic field, and carrying a unit current which flows at right angles to the lines of force, is acted on by a force tending to move it in a direction at right angles to its length, and the magnitude of this force for unit length of conductor, and unit field, is by the definition of unit current equal to unity. Applying this to our slider in which we may...
Página 860 - ... 10. That an unvarying current which, when passed through a solution of nitrate of silver in water, in accordance with the specification attached to this Report, deposits silver at the rate of 0-001118 of a gramme per second, may be taken as a current of one ampere.
Página 860 - Trade standards for multiples and submultiples of the ohm. (8) That the value of the standard of resistance constructed by a Committee of the British Association for the Advancement of Science in the years 1863 and 1864, and known as the British Association unit, may be taken as '9866 of the ohm. (9) That the standard of electrical current should be denominated the ampere, and should have the value onetenth (o'l) in terms of the centimetre, gramme, and second.
Página 859 - ... ohm. 5. That a material standard, constructed in solid metal, should be adopted as the standard ohm, and should from time to time be verified by comparison with a column of mercury of known dimensions. 6. That, for the purpose of replacing the standard, if lost, destroyed, or damaged, and for ordinary use, a limited number of copies should be constructed, which should be periodically compared with the standard ohm. 7. That resistances constructed in solid metal should be adopted as Board of Trade...
Página 527 - ... the wire to be such that its resistance is very great in comparison with that of the rest of the circuit, so that, when the slider is moved with any given velocity, the resistance in the circuit remains practically constant. When the slider is moved along the rails it cuts across the lines offeree, and so long as it moves with uniform velocity a constant difference of potentials is maintained between its two ends, and a uniform current flows in the wire from the rail which is at the higher potential...

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