## A Textbook in Electricity and Magnetism |

### From inside the book

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Page 2

We will demonstrate this for the case that m is constant F = ma Suppose now that

the force, F, is equal to

We will demonstrate this for the case that m is constant F = ma Suppose now that

the force, F, is equal to

**zero**. Then, by this law, the acceleration, a, is also equal to**zero**. What does this mean? If the acceleration is**zero**, then the velocity is ... Page 10

Since the mass in Region III has the same value as in Region I and the force is

directed in the opposite direction, the resultant force due to the Regions I and III is

...

Since the mass in Region III has the same value as in Region I and the force is

directed in the opposite direction, the resultant force due to the Regions I and III is

**zero**. In a similar manner, we can account for all the mass in the earth (Regions II...

Page 25

We have shown that the energy required to bring a mass m around an arc of a

circle concentric with m is

arcs Si, &, S3, Si, and S& is

radii ...

We have shown that the energy required to bring a mass m around an arc of a

circle concentric with m is

**zero**. Therefore, the energy required to move on thearcs Si, &, S3, Si, and S& is

**zero**. The only work done then is over the sections ofradii ...

Page 70

Since the force Qiqi/r2 is always directed along a radius it is always at right

angles to any distance ds moved along the arcs 2, 4, 6, and 8. The work to

traverse these arcs is

vectors 1, 3, 5, ...

Since the force Qiqi/r2 is always directed along a radius it is always at right

angles to any distance ds moved along the arcs 2, 4, 6, and 8. The work to

traverse these arcs is

**zero**. The only work done then occurs along the radiusvectors 1, 3, 5, ...

Page 181

As the coil turns in response to this torque, the lever arm decreases until ^\ - *-H

finally it is

the torque must be

As the coil turns in response to this torque, the lever arm decreases until ^\ - *-H

finally it is

**zero**when the coil is at right angles to the field. With the lever arm**zero**,the torque must be

**zero**. The rest position of the coil is then at right angles to the ...### What people are saying - Write a review

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2irft acceleration ammeter amperes atom axis battery body Calculate called capacitance cathode cell centimeters charge Q circuit coil Compute condenser conductor connected Consider constant copper coulomb deflection dielectric dielectric constant direction distance dynes earth effect electric field electrolyte electromagnetic electron electron volts electrostatic emitted equal equation equipotential ergs example expression field due field H filament flow flux frequency function galvanometer Gauss's law given gram gravitational grid heat impedance induced emf ionization ions kinetic energy Kirchhoff's law lines of force magnetic field mass maximum measured metal method motion moving negative charge Ohm's law ohms orbit oscillator parallel path plane plate current pole potential difference potential drop radius resistance resonance resultant rotation self-inductance series circuit shown in Fig solenoid solution sphere surface temperature thermocouple torque tube unit vacuum vector velocity voltage voltmeter volts wave wire zero zinc

### Popular passages

Page 5 - To this purpose the philosophers say that Nature does nothing in vain, and more is in vain when less will serve; for Nature is pleased with simplicity, and affects not the pomp of superfluous causes.

Page 86 - Accurate and minute measurement seems to the nonscientific imagination, a less lofty and dignified work than looking for something new. But nearly all the grandest discoveries of science have been but the rewards of accurate measurement and patient long-continued labour in the minute sifting of numerical results.

Page 32 - Every particle of matter in the universe attracts every other particle with a force proportional to the product of their masses and inversely as the square of the distance between them.

Page 34 - ... of those edifices, upright rods of iron made sharp as a needle, and gilt to prevent rusting, and from the foot of those rods a wire down the outside of the building into the ground, or down round one of the shrouds of a ship, and down her side till it reaches the water? Would not these pointed rods probably draw the electrical fire silently out of a cloud before it came nigh enough to strike, and thereby secure us from that most sudden and terrible mischief?

Page 34 - Electrical fluid agrees with lightning in "these particulars: 1. Giving light. 2. Colour of the light. "3. Crooked direction. 4. Swift motion. 5. Being con"ducted by metals. 6. Crack or noise in exploding. 7. Sub"sisting in water or ice. 8. Rending bodies it passes "through. 9. Destroying animals. 10. Melting metals.

Page 240 - Science is built up with facts, as a house is with stones. But a collection of facts is no more a science than a heap of stones is a house.

Page 5 - In experimental philosophy we are to look upon propositions inferred by general induction from phenomena as accurately or very nearly true, notwithstanding any contrary hypotheses that may be imagined, till such time as other phenomena occur, by which they may either be made more accurate, or liable to exceptions.

Page 2 - The change of motion is proportional to the motive force impressed, and is made in the direction of the right line in which that force is impressed.

Page 34 - I say, if these things are so, may not the knowledge of this power of points be of use to mankind, in preserving houses, churches, ships, etc., from the stroke of lightning, by directing us to fix, on the highest parts of those edifices, upright rods of iron made sharp as a needle, and gilt to prevent rusting, and from the foot of those rods a wire down the outside of the building into the ground, or down round one of the shrouds of a ship, and down her side till it reaches the water...

Page 178 - The most important step in the progress of every science is the measurement of quantities. Those whose curiosity is satisfied with observing what happens have occasionally done service by directing the attention of others to the phenomena they have seen ; but it is to those who endeavour to find out how much there is of anything that we owe all the great advances in our knowledge.