Engineering Physics II (For JNTUK)

272 Pages·2010·13.662 MB·English

by  S. Mani Naidu

Project Name: Engineering Physics ACE Pro India Pvt. Ltd.
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ENGINEERING PHYSICS-II
For JNTUK
Dr S. Mani Naidu
M.Sc., Ph.D., P.G.D.C.A.
Associate Professor of Physics
Sree Vidyanikethan Engineering College
Tirupati, Andhra Pradesh
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Copyright © 2012 Dorling Kindersley (India) Pvt. Ltd.
Licensees of Pearson Education in South Asia

No part of this eBook may be used or reproduced in any manner whatsoever without the publisher’s
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ISBN 9788131772416
eISBN 9788131799024

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Contents
Preface vii
Roadmap to the Syllabus ix
Chapter 1 Quantum Mechanics
and Quantum Computing 1-1
1.1 Introduction 1-1
1.2 Schrödinger’s time-independent wave equation 1-1
1.3 Physical signifi cance of the wave function 1-5
1.4 Particle in a potential box 1-5
1.5 Suitability of quantum system for information
processing 1-14
1.6 Quantum states 1-16
1.7 Classical bits 1-17
1.8 Quantum bits or qubits 1-17
1.9 Multiple qubits 1-19
1.10 Bloch sphere 1-21
1.11 Quantum gates 1-22
1.12 Advantages of quantum computing over
classical computing 1-24
Formulae 1-24
Solved Problems 1-25
Multiple Choice Questions 1-28
Answers 1-31
Review Questions 1-31
Chapter 2 Electron Theory of Metals 2-1
2.1 Introduction 2-1
2.2 Classical free electron theory of metals 2-2
2.3 Relaxation time, mean free path,
mean collision time and drift velocity 2-5
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iv Contents
2.4 Fermi-Dirac distribution 2-7
2.5 Quantum free electron theory
of electrical conduction 2-8
2.6 Sources of electrical resistance
[Electron scattering and resistance] 2-11
Formulae 2-12
Solved Problems 2-13
Multiple Choice Questions 2-20
Answers 2-22
Review Questions 2-22
Chapter 3 Band Theory of Solids 3-1
3.1 Introduction 3-1
3.2 Kronig–Penney model—origin of energy bands 3-3
3.3 Bloch theorem 3-9
3.4 Origin of energy bands formation in solids 3-10
3.5 Velocity and eff ective mass of an electron 3-11
3.6 Classifi cation of materials into conductors,
semiconductors and insulators 3-14
Formulae 3-16
Multiple Choice Questions 3-17
Answers 3-18
Review Questions 3-18
Chapter 4 Magnetic Properties 4-1
4.1 Magnetic permeability 4-1
4.2 Magnetization (M) 4-2
4.3 Origin of magnetic moment
—Bohr magneton—electron spin 4-3
4.4 Classifi cation of magnetic materials 4-5
4.5 Classical theory of diamagnetism
[Langevin theory] 4-7
4.6 Th eory of paramagnetism 4-9
4.7 Domain theory of ferromagnetism 4-12
4.8 Hysteresis curve 4-17
4.9 Anti-ferromagnetic substances 4-18
4.10 Ferrimagnetic substances [Ferrites] 4-19
4.11 Soft and hard magnetic materials 4-21
4.12 Applications of ferrites 4-22
Formulae 4-23
Solved Problems 4-23
Multiple Choice Questions 4-26
Answers 4-30
Review Questions 4-30
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Contents v
Chapter 5 Superconductivity 5-1
5.1 Introduction 5-1
5.2 General features of superconductors 5-3
5.3 Type-I and Type-II superconductors 5-7
5.4 Penetration depth 5-9
5.5 Flux quantization 5-11
5.6 Quantum tunnelling 5-12
5.7 DC and AC Josephson’s eff ect 5-14
5.8 BCS theory 5-16
5.9 Applications of superconductivity 5-19
Formulae 5-22
Solved Problems 5-23
Multiple Choice Questions 5-25
Answers 5-28
Review Questions 5-28
Chapter 6 Dielectric Properties 6-1
6.1 Introduction 6-1
6.2 Dielectric constant 6-1
6.3 Internal or local fi eld 6-2
6.4 Clausius–Mosotti relation 6-5
6.5 Orientational, ionic and electronic polarizations 6-7
6.6 Frequency dependence of polarizability:
(Dielectrics in alternating fi elds) 6-13
6.7 Piezoelectricity 6-18
6.8 Ferroelectricity 6-19
6.9 Frequency dependence of dielectric constant 6-21
6.10 Important requirements of insulators 6-23
Formulae 6-24
Solved Problems 6-25
Multiple Choice Questions 6-30
Answers 6-34
Review Questions 6-34
Chapter 7 Semiconductors 7-1
7.1 Introduction 7-1
7.2 Intrinsic semiconductors—carrier concentration 7-1
7.3 Electrical conductivity of a semiconductor 7-11
7.4 Extrinsic semiconductors 7-15
7.5 Carrier concentration in extrinsic semiconductors 7-18
7.6 Minority carrier life time 7-21
7.7 Drift and diff usion currents 7-23
7.8 Einstein’s relations 7-26
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vi Contents
7.9 Continuity equation 7-27
7.10 Hall eff ect 7-30
7.11 Direct and indirect band gap semiconductors 7-33
Formulae 7-34
Solved Problems 7-36
Multiple Choice Questions 7-43
Answers 7-46
Review Questions 7-46
Chapter 8 Physics of Nanomaterials 8-1
8.1 Introduction 8-1
8.2 Properties of nanomaterials 8-2
8.3 Preparation (Fabrication) of nanomaterials 8-5
8.4 Production of nanomaterials 8-7
8.5 Surface occupancy–Reduction of dimensionality 8-8
8.6 Quantum wells 8-9
8.7 Quantum wire 8-10
8.8 Quantum dots 8-10
8.9 Density of states and energy spectrum
of nanomaterials 8-12
8.10 Carbon nanotubes 8-14
8.11 Applications of nanomaterials 8-17
Multiple Choice Questions 8-18
Answers 8-22
Review Questions 8-23
Model Question Papers Q-1
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Preface
Th e contents of Engineering Physics-II have been designed to cater to the needs of B.Tech. students
in colleges affi liated to the Jawaharlal Nehru Technological University, Kakinada (JNTUK). Th e book
follows a simple narrative style with emphasis on clarity. Th e concepts are treated rigorously to help
students gain a deep seated understanding of the key elements intrinsic to the subject. To this end,
a list of important formulae, solved problems, multiple choice questions and review questions have
been included at the end of each chapter. Th ese pedagogical elements would prepare the student reader
to face both internal tests and term-end examinations with ease. Further, a glossary of useful terms
and a collection of previous years’ university question papers are included to enhance the book’s value
as an undergraduate text.
Th is book focuses on topics like Quantum Mechanics, Quantum Computing, Electron Th eory
of Metals, Band Th eory of Solids, Magnetic Properties, Superconductivity, Dielectric Properties,
Semiconductors and Physics of Nanomaterials.
I hope this book will be benefi cial to both students and teachers of physics at various engineer-
ing colleges under JNTUK. Comments, feedback and suggestions for the improvement of this book
are welcome. Any error that may have crept into the book inadvertently may kindly be brought to my
notice or to that of the publisher.
Mani Naidu
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Roadmap to the Syllabus
Engineering Physics-II
Jawaharlal Nehru Technological University
Kakinada
UNIT I QUANTUM MECHANICS AND QUANTUM COMPUTING
Introduction – Schrodinger time-independent and time-dependent wave equations – Particle in a
box – Operator version – Suitability of quantum system for information processing – Classical bits and
qubits – Bloch’s sphere – Quantum gates – Multiple qubits – Advantages of quantum computing over
classical computation.

REFER Chapter 1
UNIT II ELECTRON THEORY OF METALS
Classical free electron theory – Mean free path – Relaxation time and drift velocity – Quantum free
electron theory – Fermi-Dirac (analytical) and its dependence on temperature – Fermi energy –
Electron scattering and resistance.

REFER Chapter 2
UNIT III BAND THEORY OF SOLIDS
Bloch theorem (qualitative) – Kronig–Penney model – Origin of energy band formation in solids –
Classifi cation of materials into conductors, semiconductors and insulators – Concept of eff ective mass
of an electron.

REFER Chapter 3
UNIT IV MAGNETIC PROPERTIES
Permeability – Magnetization – Origin of magnetic moment – Classifi cation of magnetic materials –
Dia-, para- and ferromagnetism – Domain and Weiss fi eld theory – Hysteresis curve – Soft and hard
magnetic materials.

REFER Chapter 4
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