Practical Electricity and Magnetism |
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Page 11
... consists of brass blocks fixed to an ebonite base , and insulated from one another . They may be connected together by means of a plug , in the same way as the brass blocks in a resistance box are . The tapping key consists of a brass ...
... consists of brass blocks fixed to an ebonite base , and insulated from one another . They may be connected together by means of a plug , in the same way as the brass blocks in a resistance box are . The tapping key consists of a brass ...
Page 13
... consists of a movable brass tongue attached to a long ebonite pillar . The tongue moves between an upper and lower con- tact , both of which are highly insulated from the base ; there " " are also two detents attached to levers marked.
... consists of a movable brass tongue attached to a long ebonite pillar . The tongue moves between an upper and lower con- tact , both of which are highly insulated from the base ; there " " are also two detents attached to levers marked.
Page 17
... consisting of a piece of thick copper wire first doubled in two , the end of the resistance coil being soldered into the bend , and then one limb being bent at right A angles at the middle point , B. The object of this being to enable ...
... consisting of a piece of thick copper wire first doubled in two , the end of the resistance coil being soldered into the bend , and then one limb being bent at right A angles at the middle point , B. The object of this being to enable ...
Page 18
... consists of a number of discs of carbonized cloth , through which the current passes , and by compressing the discs the resistance can be diminished . Ranges from 500 ohms to ohm may be obtained with such instruments . C P P FIG . 14 ...
... consists of a number of discs of carbonized cloth , through which the current passes , and by compressing the discs the resistance can be diminished . Ranges from 500 ohms to ohm may be obtained with such instruments . C P P FIG . 14 ...
Page 26
... consists of three rows of resistance coils attached ELLIOTT BROS LONDONG FIG . 19 . to brass blocks fixed on an ebonite plate , and so arranged that by placing a brass plug in between two blocks the coil between them is short circuited ...
... consists of three rows of resistance coils attached ELLIOTT BROS LONDONG FIG . 19 . to brass blocks fixed on an ebonite plate , and so arranged that by placing a brass plug in between two blocks the coil between them is short circuited ...
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Common terms and phrases
adjusted altered alternating current ampères angle apparatus axis balance ballistic galvanometer ballistic swing brass bridge wire C.G.S. units calculated calibration capacity centimetre centre charged Clark cell coefficient of self-induction coherer coil condenser connected constant copper curve CuSO Daniell cell determined diameter dielectric discharged earth inductor ebonite effect electro-magnetic waves electrolyte electrometer employed ends experiment fall of potential farads galvano galvanometer needle Hence Ibid induction induction coil instrument insulated iron length lines of force liquid magnetic field magnetizing force magnetometer manganin means mercurous sulphate mercury meter method of measuring microfarads number of turns obtained ohms oscillator Phil placed plate potential difference potentiometer quadrants quantity of electricity R₁ ring rotated scale scale-divisions shown in Fig solenoid specific resistance spot of light standard cell steady currents sulphate terminals tube volt Wheatstone bridge zero zinc zinc sulphate
Popular passages
Page 105 - 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.
Page 167 - Prepare a neutral saturated solution of pure (" pure recrystallized ") zinc sulphate by mixing in a flask distilled water with nearly twice its weight of crystals of pure zinc sulphate, and adding zinc oxide in the proportion of about 2 per cent by weight of the zinc sulphate crystals to neutralize any free acid. The crystals should be dissolved with the aid of gentle heat, but the temperature to which the solution is raised should not exceed 30° C.
Page 166 - 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 0'6974 ({•£££) of the electrical pressure at a temperature of 15° C.
Page 168 - 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. The cell thus set up may be mounted in any desirable manner. It is convenient to arrange the mounting so that the cell may be immersed in a water bath up to the level of, say, the upper surface of the cork.
Page 144 - Care must be taken that the clock used is keeping correct time during this interval. The solution is now removed from the bowl and the deposit is washed with distilled water and left to soak for at least six hours. It is then...
Page 144 - C. After cooling in a desiccator it is weighed again. The gain in weight gives the silver deposited. To find the current in amperes, this...
Page 144 - The anode is then immersed in the solution so as to be well covered by it, and supported in that position ; the connections to the rest of the circuit are made.
Page 169 - It is convenient to arrange the mounting so that the cell may be immersed in a water bath up to the level of, say, the upper surface of the cork. Its temperature can then be determined more accurately than is possible when the cell is in air. In luing the cell sudden variations of temperature should as far as possible lie avoided.
Page 168 - The ends of the wire project from the ends of the tube ; one end forms the terminal, the other end and a portion of the glass tube dip into the mercury. Clean the glass tube and platinum wire carefully, then heat the exposed end of the platinum red hot and insert it in the mercury in the test-tube, taking care that the whole of the exposed platinum is covered.
Page 167 - 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 throughout the mass.