# Elementary Magnetism and Electricity: Prepared in the Extension Division of the University of Wisconsin

McGraw-Hill, 1914 - Electricity - 212 pages

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### Contents

 Preface 1 CHAPTER II 23 CHAPTER III 47 CHAPTER V 89 CHAPTER VI 105 CHAPTER VII 123
 CHAPTER VIII 143 CHAPTER IX 171 Strength of Magnetic Field and Induced Electromotive Force 177 CHAPTER X 193 Index 207 Copyright

### Popular passages

Page 205 - An erg is the work done by a force of one dyne acting through a distance of one centimeter ; or unit work is done by unit force acting through unit distance.
Page 132 - constant mass " temperature coefficient of any sample is 0.000597 + 0.000005 1 resistivity in ohms (meter, gram) at t° C. The density is 8 . 89 grams per cubic centimeter. NOTE 2. — The values given in the table are only for annealed copper of the standard resistivity. The user of the table must apply the proper correction for copper of any other resistivity. Hard-drawn copper may be taken as about 2.7 per cent higher resistivity than annealed copper.
Page 201 - This is all converted into heat and the exact relation was first determined by James Prescott Joule, an English physicist. He did this by immersing a conductor of known resistance into a known weight of water and measuring the current, time, and temperature. The results of his experiments show that the heat generated in a conductor is proportional to the time the current flows, to the resistance, and to the square of the current. This condition m&y be written in algebraic form as follows: Heat =...
Page 195 - ... In the same way the system worked upon may receive energy from the system working in the form of heat, which escapes later, and is no longer available as energy in the system worked upon. 38. Expressions for Energy. Since by definition a system possesses energy only by virtue of work done upon it, the unit of energy is the same as the unit of work, the erg. The dimensions of energy are the same as those of work, [MI?T"*~\.
Page 108 - The mass of any substance liberated by a given quantity of electricity is proportional to the chemical equivalent of the substance. The...
Page 130 - Because the area of a round wire in circular mils is equal to the square of the diameter in mils, and because the conductivity of wires of the same material are directly proportional to their area expressed in circular mils.
Page 142 - C, if the metal is in the form of a 1 cm. -cube, but since the resistance of a conductor is directly proportional to its length and inversely proportional to its cross-sectional area, it is 1'6 x 100 x 100 = 16 000 microhms = 0 '016 n if the 1 cu.
Page ii - University of Wisconsin Extension Division Norris and Smith's SHOP ARITHMETIC Norris and Craigo's ADVANCED SHOP MATHEMATICS Hills...
Page 45 - If a wire through which electricity is flowing is so grasped (Fig. 124,777) with the right hand that the thumb points in the direction of the current flow, the fingers will point in the direction of the magnetic field and vice versa.
Page 200 - This loss as previously explained, is equal to the square of the current multiplied by the resistance. The...