《医学物理学》

Chapter 1Introduction1

1.1 WHY STUDY PHYSICS？1

1.2 TALKING PHYSICS1

1.3PHYSICS FOR MEDICINE AND BIOLOGY2

1.3.1 Physics in Life Science2

1.3.2 Biomedical Applications3

1.4THE USE OF MATHEMATICS3

1.4.1 Mathematics Base3

1.4.2 Ratios and Proportions3

1.4.3 Approximation4

1.5SCIENTIFIC NOTATION AND SIGNIFICANT FIGURES6

1.5.1 Rules for Identifying Significant Figures6

1.5.2 Significant Figures in Calculations7

1.6 UNITS8

1.7 DIMENSIONAL ANALYSIS10

1.8 PROBLEM-SOLVING TECHNIQUES12

Chapter 2 Mechanics16

2.1UNIFORM CIRCULAR MOTION16

2.1.1 Angular Displacement and Angular Velocity16

2.1.2 Radian Measure17

2.1.3 Relation between Linear and Angular Speed18

2.1.4 Period and Frequency18

2.2RADIAL ACCELERATION19

2.2.1 Direction of Radial Acceleration19

2.2.2 Magnitude of the Radial Acceleration20

2.3TANGENTIAL ACCELERATION AND ANGULAR ACCELERATION22

2.3.1 Tangential Acceleration and Angular Acceleration22

2.3.2 Constant Angular Acceleration22

2.4 ROTATIONAL KINETIC ENERGY AND ROTATIONAL INERTIA23

2.5TORQUE27

2.5.1 Torque27

2.5.2 Lever Arms30

2.6 ROTATIONAL EQUILIBRIUM32

2.7ANGULAR MOMENTUM36

2.7.1 Angular Momentum36

2.7.2 The Vector Nature of Angular Momentum39

Chapter 3Fluids45

3.1 STATES OF MATTER45

3.2FLUID FLOW45

3.2.1 Types of Fluid Flow45

3.2.2 The Ideal Fluid46

3.2.3 The Continuity Equation46

3.3 BERNOULLI’S EQUATION48

3.4VISCOSITY51

3.4.1 Poiseuille’s Law53

3.4.2 Application of Viscous Flow53

3.5 VISCOUS DRAG54

3.6SURFACE TENSION55

3.6.1 Application： How Insects Can Walk on the Surface of a Pond55

3.6.2 Application： Surfactant in the Lungs56

3.6.3 Bubbles56

Chapter 4 Elasticity and Oscillations60

4.1ELASTIC DEFORMATIONS OF SOLIDS AND HOOKE’S LAW60

4.2SHEAR AND VOLUME DEFORMATIONS62

4.2.1 Shear Deformation62

4.2.2 Volume Deformation64

4.3 SIMPLE HARMONIC MOTION65

4.4THE PERIOD AND FREQUENCY FOR SHM68

4.4.1 Definitions of Period and Frequency68

4.4.2 A Vertical Mass and Spring70

4.5 GRAPHICAL ANALYSIS OF SHM72

4.6THE PENDULUM73

4.6.1 Simple Pendulum73

4.6.2 Physical Pendulum74

4.7 DAMPED OSCILLATIONS， FORCED OSCILLATIONS AND RESONANC76

Chapter 5Waves82

5.1BASIC PROPERTIES OF WAVES82

5.1.1 Waves and Energy Transport82

5.1.2 Transverse and Longitudinal Waves83

5.1.3 Periodic Waves85

5.2MATHEMATICAL DESCRIPTION OF A WAVE86

5.2.1 Traveling Waves86

5.2.2 Harmonic Traveling Waves86

5.3 GRAPHING WAVES88

5.4 PRINCIPLE OF SUPERPOSITION89

5.5REFLECTION AND REFRACTION90

5.5.1 Reflection90

5.5.2 Change in Wavelength at a Boundary91

5.5.3 Refraction91

5.6INTERFERENCE AND DIFFRACTION92

5.6.1 Interference92

5.6.2 Coherence93

5.6.3 Diffraction94

5.7 STANDING WAVES94

Chapter 6 Sound100

6.1SOUND WAVE100

6.1.1 Basic Properties of Sound Wave100

6.1.2 Frequency Ranges of Animal Hearing101

6.1.3 Attenuation of Sound Waves101

6.1.4 Amplitude and Intensity of Sound Waves102

6.2THE HUMAN EAR105

6.2.1 Structure of human Ear105

6.2.2 Loudness106

6.2.3 Pitch106

6.2.4 Localization106

6.3 BEATS106

6.4THE DOPPLER EFFECT108

6.4.1 Moving Source109

6.4.2 Moving Observer109

6.4.3 Shock Waves110

6.5ECHOLOCATION AND MEDICAL IMAGING111

6.5.1 Animal Echolocation111

6.5.2 Sonar and Radar112

6.5.3 Medical Applications of Ultrasound112

Chapter 7 Electrostatic Fields115

7.1ELECTRIC FIELDS115

7.1.1 Electric Charge115

7.1.2 Coulomb’s Law119

7.1.3 The Electric Field122

7.2 MOTION OF A POINT CHARGE IN A UNIFORM ELECTRIC FIELD130

7.3GAUSS’S LAW FOR ELECTRIC FIELDS134

7.3.1 Gauss’s Law134

7.3.2 Using Gauss’s Law to Find the Electric Field136

7.4 ELECTRIC POTENTIAL ENERGY138

7.5ELECTRIC POTENTIAL141

7.5.1 Electric Potential141

7.5.2 The Relationship between Electric Field and Potential147

7.6 CAPACITORS149

7.7DIELECTRICS152

7.7.1 Dielectrics152

7.7.2 Polarization in a Dielectric153

7.8ENERGY STORED IN A CAPACITOR156

7.8.1 Energy Stored in a Capacitor156

7.8.2 Energy Stored in an Electric Field158

Chapter 8Electric Current and Circuit163

8.1ELECTIC CURRENT163

8.1.1 Conventional Current163

8.1.2 Electric Current in Liquids and Gases164

8.1.3 Application： Current in Neon Signs and Fluorescent Lights164

8.2EMF AND CIRCUITS165

8.2.1 Circuit Symbols165

8.2.2 EMF in an Electric Circuit165

8.2.3 Circuits166

8.3MICROSCOPIC VIEW OF CURRENT IN A METAL： THE FREE-ELECTRON MODEL167

8.3.1 The Free-electron Model167

8.3.2 Relationship between Current and Drift Velocity168

8.4RESISTANCE AND RESISTIVITY169

8.4.1 Resistance and Ohm’s Law169

8.4.2 Microscopic Origin of Ohm’s Law170

8.4.3 Resistivity170

8.4.4 Resistivity of Water171

8.4.5 Resistivity Depends on Temperature172

8.4.6 Resistors173

8.4.7 Internal Resistance of a Battery173

8.5 KIRCHHOFF’S RULES174

8.6SERIES AND PARALLEL CIRCUITS175

8.6.1 Resistors in Series175

8.6.2 EMFs in Series176

8.6.3 Capacitors in Series176

8.6.4 Resistors in Parallel177

8.6.5 EMFs in Parallel180

8.6.6 Capacitors in Parallel180

8.7 CIRCUIT ANALYSIS USING KIRCHHOFF’S RULES181

8.8 RC CIRCUITS183

8.8.1 Charging RC Circuit183

8.8.2 Discharging RC Circuit185

8.8.3 Application of RC Circuits in Neurons185

Chapter 9 Magnetic Forces and Fields190

9.1 MAGNETIC FIELDS190

9.1.1 Permanent Magnets and Magnetic Dipoles190

9.1.2 Magnetic Field Lines192

9.1.3 The Earth’s Magnetic Field192

9.1.4 Application： Magnetotactic Bacteria193

9.2 MAGNETIC FORCE ON A POINT CHARGE193

9.2.1 Cross Product of Two Vectors194

9.2.2 Direction of the Magnetic Force195

9.3 MOTION OF A CHARGED PARTICLE IN A UNIFORM MAGNETIC FIELD199

9.3.1 Charged Particle Moving Perpendicularly to A Uniform Magnetic Fiel199

9.3.2 Motion of A Charged Particle in A Uniform Magnetic Field： General203

9.3.3 A Charged Particle in Crossed E and B Fields204

9.4 MAGNETIC FORCE ON A CURRENT-CARRYING WIRE208

9.5 TORQUE ON A CURRENT LOOP210

9.5.1 Torque on a Magnetic Dipole211

9.5.2 Application： Electric Motor211

9.5.3 Application： Galvanometer212

9.5.4 Application： Audio Speakers213

9.6 MAGNETIC FIELD DUE TO AN ELECTRIC CURRENT214

9.6.1 Magnetic Field due to a Long Straight Wire214

9.6.2 Magnetic Field due to a Circular Current Loop216

9.6.3 Magnetic Field due to a Solenoid217

9.6.4 Application： Magnetic Resonance Imaging218

9.7 AMPERE’S LAW218

9.8 MAGNETIC MATERIALS219

9.8.1 Paramagnetism220

9.8.2 Ferromagnetism220

9.8.3 Diamagnetism221

9.8.4 Application： Electromagnets221

9.8.5 Application： Magnetic Storage221

Chapter 10Electromagnetic Induction226

10.1 MOTIONAL EMF226

10.2FARADAY’S LAW， LENZ’ S LAW， EDDY CURRENTS229

10.2.1 Faraday’s Law229

10.2.2 Lenz’s Law233

10.2.3 Eddy Currents236

10.3INDUCED ELECTRIC FIELDS， INDUCTANCE237

10.3.1 Induced Electric Fields237

10.3.2 Inductance238

10.4 LR CIRCUITS241

10.5 MAXWELL’S EQUATIONS AND ELECTROMAGNETIC WAVES244

10.5.1Accelerating Charges Produce Electromagnetic Waves244

10.5.2 Maxwell’s Equations245

10.6 THE ELECTROMAGNETIC SPECTRUM245

10.6.1Visible Light246

10.6.2 Infrared246

10.6.3 Ultraviolet247

10.6.4 Radio Waves248

10.6.5 Microwaves248

10.6.6 X-Rays and Gamma Rays249

Chapter 11 Geometric Optics253

11.1THE FORMATION OF IMAGES THROUGH REFLECTION OR REFRACTION253

11.1.1 Real and Virtual Images253

11.1.2 Plane Mirrors254

11.2SPHERICAL MIRRORS254

11.2.1 Convex Spherical Mirror254

11.2.2 Concave Spherical Mirror256

11.3THIN LENSES256

11.3.1 Focal Points and Principal Rays257

11.3.2 The Magnification and Thin Lens Equations258

11.4LENSES IN COMBINATION260

11.4.1 Ray Diagrams for Two Lenses260

11.4.2 Transverse Magnification261

11.5THE EYE263

11.5.1 Accommodation264

11.5.2 Application： Correcting Myopia264

11.5.3 Application： Correcting Hyperopia265

11.6COMPOUND MICROSCOPES AND ABERRATIONS OF LENSES AND MIRRORS268

11.6.1 Compound Microscope268

11.6.2 The Transmission Electron Microscope269

11.6.3 Aberrations of Lenses and Mirrors270

Chapter 12Wave Properties of Light275

12.1HUYGENS’S PRINCIPLE275

12.1.1 Sources of Light275

12.1.2 Wavefronts and Rays275

12.1.3 Huygens’s Principle276

12.2CONSTRUCTIVE AND DESTRUCTIVE INTERFERENCE277

12.2.1 Coherent and Incoherent Sources277

12.2.2 Interference of Two Coherent Waves278

12.2.3 Phase Difference due to Different Paths279

12.3THIN FILM281

12.3.1 Phase Shifts due to Reflection282

12.3.2 Problem-Solving Strategy for Thin Films283

12.3.3 Thin Films of Air284

12.4 YOUNG’S DOUBLE-SLIT EXPERIMENT287

12.5 GRATINGS290

12.6DIFFRACTION AND RESOLUTION OF OPTICAL INSTRUMENTS293

12.6.1 Diffraction by a Single Slit293

12.6.2 Diffraction and Resolution of Optical Instruments296

12.7 X-RAY DIFFRACTION299

12.8POLARIZATION300

12.8.1 Linear Polarization300

12.8.2 Circular Polarization302

12.8.3 Polarizers302

12.8.4 Polarization by Scattering304

12.8.5 Polarization by Reflection308

Chapter 13THE BASIS OF QUANTUM MECHANICS313

13.1 QUANTIZATION313

13.2 BLACKBODY RADIATION314

13.3THE PHOTOELECTRIC EFFECT315

13.3.1 Experimental Results315

13.3.2 The Photon316

13.3.3 The Electron-Volt318

13.3.4 The Photon Theory Explains the Photoelectric Effect318

13.3.5 Applications of the Photoelectric Effect319

13.4 X-RAY PRODUCTION319

13.5 COMPTON SCATTERING321

13.6THE WAVE-PARTICLE DUALITY AND MATTER WAVES323

13.6.1 Double-Slit Interference Experiment323

13.6.2 Matter Waves324

13.6.3 Matter Waves and Probability327

13.7 ELECTRON MICROSCOPES327

13.8THE UNCERTAINTY PRINCIPLE329

13.8.1 Position-momentum uncertainty principle329

13.8.2 Energy-Time Uncertainty Principle331

Chapter 14Nuclear Physics335

14.1NUCLEAR STRUCTURE AND BINDING ENERGY335

14.1.1 Nuclear Structure335

14.1.2 Sizes of Nuclei336

14.1.3 Binding Energy337

14.1.4 Binding Energy and Mass Defect338

14.1.5 Nuclear Energy Levels340

14.2RADIOACTIVITY341

14.2.1 Conservation Laws in Radioactive Decay342

14.2.2 Alpha Decay343

14.2.3 Beta Decay344

14.2.4 Gamma Decay346

14.2.5 Other Radioactive Decay Modes347

14.3RADIOACTIVE DECAY RATES AND HALF-LIVES347

14.3.1 Radioactivity Decay Law347

14.3.2 Application： Radiocarbon Dating349

14.4BIOLOGICAL EFFECTS OF RADIATION351

14.4.1 Radiation Dose351

14.4.2 Penetration of Radiation354

14.4.3 Medical Applications of Radiation354

Appendix AEnglish-Chinese Index359

Appendix BTable of Selected Nuclides363

Answers to Problems366