PHYSICS Made Simple

Ira M. Freeman, Ph.D.

Advisory editor Wesley Morgan, BSc., M.Ed., M.1nst.P.

Made Simple Books W. H. ALLEN London A Howard & Wyndham Company

Table of Contents

SECTION ONE-MATTER

1 MATTER AND ENERGY Three Forms of Matter

Solid Liquid Gas

2 HOW WE MEASURE THINGS Measurement of Length The Metric System: The Metre Measurement of Area and Volume

The Units of Measurement Measuring Mass and Weight

The Kilogram Time The Second Derived Units: Densitv

~undamentai Units Area and Volume SI Units

3 LIQUIDS Liquid Pressure

What is Force ? What is Pressure ? Pressure Depends on Depth

Calculating the Pressure Applications of Fluid Pressure

Buoyancy and Flotation Archimedes' Law of Buoyancy Applications of Flotation

4 THE AIR AND OTHER GASES Air Pressure The Barometer

Torricelli's Experiments

vii

I nr; firmoxpnen: Boyle's Law

Buoyancy in Gases Uses of Air Pressure

Air Resistance The Aeroplane; Bemouili's Law

Other Applications

SECTION TWO-FORCE, MOTION, AND ENERGY

FORCES Representation of Forces; Vectors Resultant of a Set of Forces Eauilibrium of Forces Gutre of Gravity Torque and Rotation Gravitation

MOTION Speed and Velocity Acceleration

Motion with Constant Acceleration Falling Motion; Projectiles

Force and Motion Newton's Laws

Law of Inertia Centrioetal Force: Satellites The ~ i c o n d Law . The Third Law; Action and Reaction

Rotational Inertia

WORK, ENERGY, AND MACHINES

1 Work l The Energy Principle

Potential Energy I i

Kinetic Energy Power Machines

Perpetual-motion Machine

8 MOLECULES Atoms and Molecules The Kinetic Theory Gas Pressure Molecular Forces in Solids Other Properties of Solids Surface Tension Capillarity

SECTION THREE-HEAT

9 THE NATURE OF HEAT Temperature and Its Measurement Expansion of Solids and Liqu~ds Expansion of Gases; Absolute Temperature Conduction of weat Convection Radiat~ou

10 HEAT ENERGY Quantity of Heat

Heat Units Fusion of a Solid Vaporization of a Liquid

Moisture in the Air Conservation of Energy Heat Engines Refrigeration

SECTION FOUR-SOUND

11 THE NATURE OF SOUND Sound Waves

Temperature Effects Reflection of Waves Continuous Waves

Frequency and Wavelength

12 ACOUSTICS Pitch and Frequency Intensity and Loudness

Indoor Sound Stationary Waves

Vibrations of Strings Waves in a Pipe

Resonance; Forced Vibrations Quality of Sounds

13 LIGHT AND LIGHTING Light Travels in Straight Lines Speed of Light

Y.5.'. .,"-K" --<

Filament Lamp 129 Carbon Arc 130 Tube-type Lighting 130 Fluorescent Lamps 130

Illumination 130 Theories of Light 133

14 REFLECTION AND REFRACTION OF LIGHT 136

1 Reflection of Light 136 > 'l

Law of Reflection 136 U Plane Mirror 138 i. Curved Mirrors 139

Refraction of Light 141 Law of Refraction 141 Wave Theory of Refraction 142

. Total Reflection; Mirages 143 Lenses 145

Image Formation 146 Diverging Lenses 147

Some Optical Instruments 148 Camera and Eye 148 Microscopes and Telescopes 149

15 WAVE OPTICS AND COLOUR 154 The Spectrum 154

Colour Mixing 156 Mixing Pigments 157

The Spectroscope 158 Electromagnetic Waves 159 Diffraction 160 Interference 162 Polarization 164

SECTION SIX-MAGNETISM AND ELECTRICITY

16 MAGNETS AND ELECTRIC CHARGES Magnetism

Magnet Poles Magnetic Fieldr The Earth's Magnetism

Static Electricity Electric Charges Atoms and Electricity Conductors and Insulators Electrostatic Induction Electric Fields Potential and Capacitance

17 ELECTRIC CURRENTS Current Strength Action of a Cell; Ions Batteries Electrolysis A Simple Circuit Ohm's Law

PD in a Circuit Resistors in Series Resistors in Parallel

Electric Power and Energy

18 HEATING AND MAGNETIC EFFECTS OF ELECTRIC CURRENTS

Heat Developed in a Conductor Applications of the Heating Effect

Oersted's Discovery Field Due to a Current Coils Uses of Electromagnets Force on a Current Moving-coil Meters Motors

19 INDUCED CURRENTS Faraday's Experiments Electromagnetic Induction Lenz's Law Generators ! Generating DC

1. j

Back Voltage 1 The Transformer I The Telephone t Other Sound Reproducers ; i

Eddy Currents I

SECTION SEVEN-ELECTRONICS AND NUCLEAR PHYSICS

C The Transistor

The Electron Microscope The Photoelectric Effect The Quantum Theory

21 NUCLEAR PHYSICS Positive Rays; Mass Spectra

Natural Radioactivity Size of the Nucleus; Bohr's Theory Artificial Nuclear Changes Mass-Energy Equivalence

Einstein's Theory of Relativity Radio-isotopes Cosmic Rays Elementary Particles Nuclear Fission Nuclear Reactors; Fission Bombs

Uses of Reactors Nuclear Fusion

ANSWERS AND SOLUTIONS

IMPORTANT FORMULAE AND RELATIONS

Baryons, 243 Batteries, 183-186 car, 25 See also Electric drcuits

Becquerel, A. H., 237 Bernoulli's Law, 34-36 Beta rays, 238 Betatron, U 3 Bethe, Hans, 247 Bimetal, 83-84 Binocular, prism, 144,15&1! Bohr, Niels, 239 Boiling, %

at reduced pressure., 97 Boiling point, 62 Bombs

atomic. 245 thermonuclear, 247

Boyle, Robed, 31 Boyle's Law 31-32,71,261 ~rownian mbtion, 70 Brushes (motors), 203 Btu. 94.262

Calorie, 94 Cameras, 148. 160

pinhole. 128 Capacitance, 179-181 Capacit?~, 181 Capillanty, 75-76 Carbon arc. 130 Carburettor, 35 Car lift, 22 Cathode rays, 221-227 Cells, 184-185

dry, 185 lead storage, 185-186 photrooic. 230 voltaic. 184

Celsius system, 82,262 Centre of granty, 4- Centigrade system.

See Celsius system Centrifuge, 56 Centripetal force, 56 Chain reaction, 244-245 Charges. See Electric charges Chemical changes, 4 Circuits. See Electric circuits Clarinet, 121.123

265

Index -

Clouds, 97 Coal, 90 Coal mines, 87 Coefficients

heat-conduction, 87 of linear expansion, expansivity, 83

Cohesion in solids, 73 Coils, 198-216

in generators, m-212 resistance of, 189-190

Cold, 90 See dso Heat; Temperature

Colloidal suspension, 3 Colour, 156166

mixing of, 155-158 in nhotoeraohv. 158 -~ . . ~+q,-l5ti pnntrng processes for, 157-158 spectrum of, 154-156, 159 white lieht and. 156156

~ommutaTor, 203 Compass needle, 172, 197 Compounds, chemical, 3 Conduction of heat, 86-88 Conductors of electricity

heat developed in, 195-197,263 insulators and, 176-178

Conservation of energy. M, 66,9&99 Convection. 8&89 Corpuscul& theory, 133 Cosmic rays, 242 Coulomb, 179 Critical size. 245 Crystalline structure, 70 Curie, Marie, 237 Curie, Pierre, 237

-Currents. See Electric currents Cyclotron, 240

- Daw. Sir Humoh. 87 h ay; ineasurement-of, 12 DC (direct current), 211 Decibel. 116 - - ~

De Porest, Lee, 224 Democritus, 69 Density, 23-25

formula for, 13,261 measuring, 13-15 of relative (sp56c gravity), 24

Depth and liquid pressure. 18-22 Derived units, 13 Detector (electronics), 224225 Deuterium, 236 Diamonds, 74 Diffraction, I s 1 6 2 Diffraction gratings, 162 Diode, 223 Direct current, 211 Dispersion of colour, 154-156

Electric Hbpliances, power in, 263

Electric charges, 174-178 Electlic circuits, 187-189

fuses and, 196 measurement of, 187 Ohm's Law, 188-192,263 resistors in. 189-192 'short' in, 192

Electlic currents, 175, 183-217 batteries and, 183-186 heating effects of, 195-197 induction of, 207-216 magnetic effects of, 197-ZM stepping up and down, 212-214 strength of, 183-184 263 See also Electric ciriuits

Electric fields, 179 Electric generators, 209-212 Electric motors, 203-204,211-214

induction, 216 Electric organ, 215 Electric power and energy, 192-193 Electricity, 174-217

atoms and, 175-176 photo-, 230 static, 174-175

Electrolysis, 186-187 Electromagnetic waves, 134, 159- Electromagnets, 198-200 Electronics, 221-233 Electron microscope, 150,229 Electrons, 175, 222 Electron tubes, 223-225 Electrophorus, 178 Electroplating, 187 Electrostatic force, 17&181 Electrotypes, 187 Elementary panicles, 175, 242-243 Elements. 3

See also Atoms Emulsion, 3 Energy, 6,6244 chemical. 6.90 conservation of, M, 66,98-99

kinetic,' 6264, 262 mass-energy equivalence, 24&241,

247. 264

seat, 99 jet-propulsion, 58, 99

Equilibrium of forces. 43-44 of torques, 261

Erg, 63 Ether', 134

Evaporation. 70. 96-97 Exponents, il Exposure meters, 132 Eve. human. 148-149 Eiepiece (optics), 150

Fahrenheit, 82, 262 Falling motion, 53-54 Faraday, Michael, 172, 206 Fathometer, 108 Fields

due to current, 197-U)4 electric, 179 magnetic, 171-172 rotating magnetic, 216

Filament lamp, 129, 130, 188, 195- Fission, nuclear, 243-246 Fleming, Sir John, 223 Flotation, 22-25 Fluorescent lamps, 130 Flute, 121, 123 Flute, magnetic, 207 Flux, magnetic, 207 FM (frequency modulation), 225 Foam, 3 Focal length, 140, 145 Focus

principal, 140, 146 virtual, 148

Fog, 97 Foot-candle, 131 Foot pounds, 64 Force (form), 42-50

centnpetal, 55-56 compared, 180 drag, 36 electric fields and, 180 equilibrium of, 43-44 lines of, 207-208 liquid pressure and, 17-18 magnetic lines of, 172 molecular, 73-74 motion and, 55-59

.-r.---- ""- -., resultant of, 4243 torque and rotation, 4-8 work and, 6142,262 See also Gravity

Formulas, 261-264 Franklin, Beqjamin, 175 Freezing, 95-96 Freezing point, 81-82 Frequency

pitch and, 11&115 ultrasonic, 114 wavelength and, 11&112

Frequency modulation, 225 Frost, 97 Fundamental tone, 119 Fundamental particles, 176,242. Fundamental units, 13 Fuses. 196 Fusion

heat of, 95 nuclear, 246-247 of solid, 95-96

G Galileo, 28, 53, 55 Galvani, Luigi, 184 Gamma rays, IM), 238,245 Gases, 3

buovancv h. 31-32 exp&ioin of. 8&86 pressure of, 71-72 See also Air

Gas refrinerator. 100

Hail, 97 Hahn, Otto, 243 Half-life, 239

I.-""-, I-.

Harmonics, 119, 122 H-bomb. 247 Heat, 81-101, 195205

conduction of, 86-88 wnductor - developed, 195-19 convection and. 88-89 ermines. 99 )fXlament lamps. 195

i of fusion. 95 nature of, 81-92

F quantity of, 93-95.262 s d c . 93

i &its of, 94 of vaporization, 96 See also Temperature

F Ha , e r , 9,101 1 Heat-work equivalent, 98,262

Helicopter, 35 i , O S ~ O ~ . 206

Luminous inrensily, 130 Luminous watch dial, 239

Neon lighting, 130 Neutrons. 236, 243 Newton. Sir Isaac 133, 154

Law of ~ravitafion, 49 Laws of Motion, 55-59,262

Newton. forcc of, 61-62 Nodes (acoustics). 118

Particles, fundamental, 176,242-243 PD. See Potential ~~

Planck, Max, 231 Plasma cleFtrical, 247

type metal in, 96 Prism 154-156 ~rism'binocular, 144 151 Projecwes, 53-54,~i-fig Protons, 175,243

Q Quantum thwry, 231-232,239

R Radar, 229

Doppler effect and, 115 Radiation heat, 89-91 Radio, 225-226 Radioactivity, 237-247

cosmic rays, 242 natural, 237-239

Radio capacitor, 181 Radio-isotopes, 242 Radio tubes, 226 Radium 237,239 Rain, 91 Rainbow, 156 Rays

alpha, 238-242 beta, 238 cathode, 221-222.227 &F, 242 pamma, 160,238,245

~efleciion of light, 136-141,143-145 of waves, 107-108

Refraction of light, 141-143 index of, 143,263 wave thwly of, 142-143 See also Lenses

Refrigerators, 88, 99-1M) Relativity, Theory of, 241 Relay, 200 Resistance, air, 32134 Resistance thermometer, 189 Resistors, 189-192

in parallel, 1%192.263 in series, 190, 263 starting box. 212

Resonance, 121-122 Retina, 148 Reverberation time, 116 Right Hand Rules, 198 Rockets, 58-59,99 Roentgen, W. C., 222 RBmer, Olaus, 129 Rotation. 4?! 261 Rotational mntxa, 59 Rutherford. Emest, 237-241

Semiconductors, &227 Ships

displacement of, 23-24 sinking, 24-25

Short-circuit, 192 Shortsighted eye, 149 Shunt, 192 Simiiicant diaits. 11

Snow, 97 Soap film. 163 Solenoid, 19&199 Solids, 3, ,73-74

crvstall~ne structure of. 70 ivaporation of, 70 '

expansion of, 83-84 fusion of, 95-96 molecular forces in, 73-74 mol~ular properties of, 74

Sound, 105-124 indoor, 116

in musi&i~&&ents, 118-123 pitch and frequency, 114-115 quality of, 122-123 reflection of, 107-108 reproducers of, 214-215 S@ of, 106 temperature and, 106-107 vibrations and. 111

continuous, 159 Speed, 5132,261

air resistance and. 32-33 wnversion factors for units of,

51

Tape-recorder, 215 Telephone, 214215 Telescopes. 149-151

reflecting, 140,150 refracting, 154

Television, 227-228 Temperature, 81-82

abolute, 84-86 Celsius, 82, 262 Fahrenheit, 82, 262 measurement of, 81-82 sound and, 106-107 various objects, 86 See also Heat

Tennis hall, curving of, 36 Tensile strength (tenacity), 73

Thermal Unit, ~ritish, 94, 262 Thermionic emission, 223 Thennometers

gas, 85 mercury. 81-82 resist&&, 189

Thermonuclear kmmb, 247 'Thennos' bottle, 87 Thermostat, 84 Thomson, J. J., 222, 227,234,235 Thunder. l07 Tides, 49 -- ~

Time, 12-13 Tone, 114

fundamental, 119 quality of, 122-123

Torque, 4648,261 equlllbrium of. 261

Tonicelli, Evangelists, Transformer, 212-214, Transistor, 226-227 Triode. 224,226 Turning effect, 47 Type metal, 96

, . C',

~' . . , . '.,*

.. .,,.

transverse, 110 ulbaviolet, 159 See also L i t

Weight, 56 .13 of air, 27 measurement of, 12 of ships, 23-24

Whispering galleries, 108 White l i t , 154-156 Wind 89 wmd'instruments, 119-120 Work, 61-62

d e w , 61 formulas for, 61, 64,262 heat and. 98,262 mechanical energy and, 63-64 rate of doing, 65

X X-rays, 160

product~on of, 222223 Y

Yard, Standard, 9