Ncert Class 12th Physics Index

CONTENTS FOREWORD PREFACE

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CHAPTER ONE ELECTRIC CHARGES AND FIELDS 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 1.10 1.11 1.12 1.13 1.14 1.15

Introduction Electric Charges Conductors and Insulators Charging by Induction Basic Properties of Electric Charge Coulomb’s Law Forces between Multiple Charges Electric Field Electric Field Lines Electric Flux Electric Dipole Dipole in a Uniform External Field Continuous Charge Distribution Gauss’s Law Application of Gauss’s Law

1 1 5 6 8 10 15 18 23 25 27 31 32 33 37

CHAPTER TWO ELECTROSTATIC POTENTIAL AND CAPACITANCE 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10 2.11 2.12 2.13

Introduction Electrostatic Potential Potential due to a Point Charge Potential due to an Electric Dipole Potential due to a System of Charges Equipotential Surfaces Potential Energy of a System of Charges Potential Energy in an External Field Electrostatics of Conductors Dielectrics and Polarisation Capacitors and Capacitance The Parallel Plate Capacitor Effect of Dielectric on Capacitance

51 53 54 55 57 60 61 64 67 71 73 74 75

2.14 Combination of Capacitors 2.15 Energy Stored in a Capacitor 2.16 Van de Graaff Generator

78 80 83

CHAPTER THREE CURRENT ELECTRICITY 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16

Introduction Electric Current Electric Currents in Conductors Ohm’s law Drift of Electrons and the Origin of Resistivity Limitations of Ohm’s Law Resistivity of various Materials Temperature Dependence of Resistivity Electrical Energy, Power Combination of Resistors — Series and Parallel Cells, emf, Internal Resistance Cells in Series and in Parallel Kirchhoff’s Laws Wheatstone Bridge Meter Bridge Potentiometer

93 93 94 95 97 101 101 103 105 107 110 113 115 118 120 122

CHAPTER FOUR MOVING CHARGES AND MAGNETISM 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11

Introduction Magnetic Force Motion in a Magnetic Field Motion in Combined Electric and Magnetic Fields Magnetic Field due to a Current Element, Biot-Savart Law Magnetic Field on the Axis of a Circular Current Loop Ampere’s Circuital Law The Solenoid and the Toroid Force between Two Parallel Currents, the Ampere Torque on Current Loop, Magnetic Dipole The Moving Coil Galvanometer

132 133 137 140 143 145 147 150 154 157 163

CHAPTER FIVE MAGNETISM AND MATTER 5.1 5.2 xiv

Introduction The Bar Magnet

173 174

5.3 5.4 5.5 5.6 5.7

Magnetism and Gauss’s Law The Earth’s Magnetism Magnetisation and Magnetic Intensity Magnetic Properties of Materials Permanent Magnets and Electromagnets

181 185 189 191 195

CHAPTER SIX ELECTROMAGNETIC INDUCTION 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10

Introduction The Experiments of Faraday and Henry Magnetic Flux Faraday’s Law of Induction Lenz’s Law and Conservation of Energy Motional Electromotive Force Energy Consideration: A Quantitative Study Eddy Currents Inductance AC Generator

CHAPTER SEVEN ALTERNATING CURRENT 7.1 Introduction 7.2 AC Voltage Applied to a Resistor 7.3 Representation of AC Current and Voltage by Rotating Vectors — Phasors 7.4 AC Voltage Applied to an Inductor 7.5 AC Voltage Applied to a Capacitor 7.6 AC Voltage Applied to a Series LCR Circuit 7.7 Power in AC Circuit: The Power Factor 7.8 LC Oscillations 7.9 Transformers

204 205 206 207 210 212 215 218 219 224

233 234 237 237 241 244 252 255 259

CHAPTER EIGHT ELECTROMAGNETIC WAVES 8.1 8.2 8.3 8.4

Introduction Displacement Current Electromagnetic Waves Electromagnetic Spectrum

ANSWERS

269 270 274 280 288

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