Elementary Lessons in Electricity & Magnetism

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Macmillan, 1894 - Electric power - 638 pages

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Page 586 - As a umt of resistance, the international ohm, which is based upon the ohm equal to 109 units of resistance of the Centimetre-Gramme-Sevond 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 grammes in mass, of a constant cross-sectional area and of the length of 100-3 centimetres.
Page 588 - As a unit of work, the joule, which is equal to 107 units of work in the CGS system, and which is represented sufficiently well for practical use by the energy expended in one second by an international ampere in an international ohm. As a unit of power, the watt, which is equal to 10...
Page 591 - ... above the cork, using sufficient to cover completely the zinc and soldering. The glass tube containing the platinum wire should project some way above the top of the marine glue. The cell may be sealed in a more permanent manner by coating the marine glue, when it is set, with a solution of sodium silicate, and leaving it to harden.
Page 587 - The unit of quantity shall be what is known as the international coulomb, which is the quantity of electricity transferred by a current of one international ampere in one second. Fifth. The unit of capacity shall be what is known as the international farad, which is the capacity of a condenser charged to a potential of one international volt by one international coulomb of electricity.
Page 590 - ... temperature, agitating it from time to time, then allow it to cool ; continue to shake it occasionally while it is cooling. Crystals of zinc sulphate should then be distinctly visible, and should be distributed throughout the mass ; if this is not the case, add more crystals from the stock bottle, and repeat the whole process. This method ensures the formation of a saturated solution of zinc and mercurous sulphates in water. To set up the Cell. The cell may conveniently be set up in a small test...
Page 587 - The unit of current shall be what is known as the international ampere, which is onetenth of the unit of current of the centimeter-gramsecond system of electro-magnetic units, and is the practical equivalent of the unvarying current, which, when passed through a solution of nitrate of silver in water...
Page 587 - As a unit of electromotive force, the international volt, which is the electromotive force that, steadily applied to a conductor whose resistance is one international ohm, will produce a current of one international ampere, and which is represented sufficiently well for practical use by ^2.
Page 590 - C. Keep the paste for an hour at this temperature, agitating it from time to time, then allow it to cool ; continue to shake it occasionally while it is cooling. Crystals of zinc sulphate should then be distinctly visible, and should be distributed...
Page 589 - The Zinc. — Take a portion of a rod of pure redistilled zinc, solder to one end a piece of copper wire, clean the whole with glass paper, carefully removing- any loose pieces of the zinc.

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