Engineering Physics − Theory and Practical

378 Pages·2015·30.198 MB·English

by  A. K. Katiyar, C. K. Pandey

Engineering Physics
Theory and Practical
Prof. A. K. Katiyar
Institute of Engineering and Technology
Sitapur Road, Lucknow
Uttar Pradesh, India
Dr. C. K. Pandey
Maharana Institute of Technology and Sciences
Mohanlalganj, Raebareilly Road, Lucknow
Uttar Pradesh, India
Engineering Physics
Theory and Practical
Copyright © 2015 by Wiley India Pvt. Ltd., 4435-36/7, Ansari Road, Daryaganj, New Delhi-110002.
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Edition: 2015
ISBN: 978-81-265-5454-6
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Preface
It is our privilege to bring out the present book titled “Engineering Physics − Theory and Practical” for engi-
neering students of U. P. Technical University, Lucknow. It is well known that Physics is not only the basic
subject from which all the branches of engineering are derived but is also used in most of the technological
developments and their advancements. In this regards, it becomes the compulsory course for all engineering
graduated students. Since U. P. Technical University has revised the syllabus of Engineering Physics from
academic session 2013−14, therefore the present textbook is an attempt to fulfil the needs of all engineering
students according to the new revised syllabus.
The subject matter in the book has been presented in easy, effective and systematic way starting from
basic concepts for the sake of continuity and better understanding of the subject. The whole subject matter
has been divided into theory and practical sections as per the UPTU syllabus.
The University runs two courses of Engineering Physics (NAS-101 and NAS-201) in first and second
semester, respectively. Therefore, the theory section of the book contains entire syllabus of both courses pre-
sented in 14 chapters according to the papers. Chapters 1−7 contain the syllabus of first paper (NAS-101)
and Chapters 8−14 contain the syllabus of second paper (NAS-201).
Organization of the Book
NAS-101
1. Chapter 1 of the book explains the relativistic mechanics (Unit-I).
2. Chapter 2 describes the fundamentals of modern physics (Unit-II).
3. Physical optics of Unit-III Interference, Diffraction and Polarization is presented through Chapters 3,
4 and 5, respectively.
4. Chapters 6 and 7 cover laser, fibre-optics and holography of Unit-IV.
NAS-201
1. Chapter 8 explains the crystal structure and X-ray diffraction of Unit-I.
2. Chapters 9 and 10 contain dielectric and magnetic properties of materials of Unit-II.
3. Unit-III consists the electromagnetic theory describes through Chapter 11.
4. Some technologically important materials such as semiconductors, superconductors and n anomaterials
of Unit-IV are expressed through Chapters 12, 13 and 14, respectively.
Lab Manual
The practical section of book contains detailed theory, method, observation table and question and answer
for viva-voce. It provides complete information on all experiments prescribed as per UPTU syllabus.
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iv • Preface
Salient Features
1. Every topic is written and explained in a systematic and step-wise manner so that anyone can
understand the subject without any difficulties. The language used is so lucid and comprehensive that
a student lacking good knowledge of the subject can also be equally benefitted.
2. Review questions (related to the topics) and important points are provided at the end of the each
chapter for further exposure and memories the contents.
3. Numerical problems with step-by-step solutions are provided in each chapter for understanding and
practice.
4. Lab Manual: The experiments and their viva-voce aspect are incorporated in a very simple and
systematic way in this book.
Acknowledgements
We owe a deep sense of gratitude to Manisha Bajpai, PDF Allahabad University, Allahabad and
Dr. S. A. Warsi SRMCEM, Lucknow for providing us enough opportunities for interacting with them on
the topics covered in the present book. We are thankful to publishers WILEY for providing constant sup-
port during the work and bringing the book in such a nice form. Although we have made our best efforts
for error-free book, we would be glad to know any misprint omission that has crept in the printed matter or
any genuine and constructive suggestions for improving the quality of the present textbook.
Authors
April 03, 2015
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About the Authors
Dr. A. K. Katiyar is Professor in Department of Applied Sciences, Institute of
Engineering & Technology, Lucknow. He obtained his Ph.D. in Physics (with
specialization in Atomic collision) from University of Roorkee (presently IIT
Roorkee) in 1988. He completed M.Sc. Physics (specialization in Electronics
& Atmospheric Sciences) from University of Roorkee and B.Sc. Physics and
Maths from Garhwal University, Srinagar in 1984 and 1981, respectively. He
has many years of teaching and research experience in various engineering
institutes. He has published more than 40 research papers in different reputed
International and National journals/conferences and attended various International and National con-
ferences. Dr. Katiyar has authored of two books for the engineering students. He is also a referee of
various reputed International journals.
Dr. C. K. Pandey obtained Ph.D. in Physics (with specialization in non-
conventional energy – Solar Energy) from Uttar Pradesh Technical University
(UPTU) in 2012. He completed M.Sc. Physics ( specialization in Electronics)
in 2005 and B.Sc. Physics and Maths in 2003 both from CSJM University,
Kanpur. He teaching and research experience spans nine years. He has
published 30 research papers of which 23 are in reputed International and
national Journals in the field of energy. He is also a r eferee of various reputed
International journals.
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Contents
Preface iii
About the Authors v
Chapter 1 Relativistic Mechanics 1
Learning Objectives 1
1.1 Introduction 1
1.2 Some Important Terms 2
1.3 Frame of Reference 2
1.3.1 Inertial Frames of Reference 2
1.3.2 Non-Inertial Frames of Reference 3
1.4 Earth: Inertial or Non-Inertial Frame of Reference? 3
1.5 Ether Hypothesis 3
1.6 Michelson−Morley Experiment 3
1.6.1 Explanation of the Negative Results of Michelson−Morley Experiment 5
1.6.2 Conclusions of Michelson−Morley Experiment 5
1.7 Einstein’s Postulates of Special Theory of Relativity 5
1.8 Galilean Transformation 6
1.8.1 Failure of Galilean Transformation 7
1.9 Lorentz Transformations 8
1.10 Inverse Lorentz Transformations Equations 9
1.11 Consequences of Lorentz Transformations 9
1.11.1 Length Contraction 10
1.11.2 Time Dilation 11
1.11.3 Experimental Verification of Time Dilation (Example of Real Effect) 12
1.12 Twin Paradox in Special Relativity 12
1.13 Transformation of Velocities or Addition of Velocities 13
1.14 Variation of Mass with Velocity 14
1.15 Expression for the Relativistic Kinetic Energy 16
1.16 Einstein’s Mass−Energy Relation 18
1.17 Relativistic Relation between Energy and Momentum 19
1.18 Massless Particles 19
Solved Examples 19
Short Answers of Some Important Questions 28
Important Points and Formulas 29
Multiple Choice Questions 30
Short Answer Type Questions 31
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viii • contents
Long Answer Type Questions 31
Numerical Problems 32
Answers 32
Chapter 2 Wave Mechanics 33
Learning Objectives 33
2.1 Introduction 33
2.2 Wave-Particle Duality 33
2.3 de-Broglie Hypothesis 34
2.4 de-Broglie’s Wavelength 34
2.5 de-Broglie Wavelength for a Free Particle in Terms of its Kinetic Energy 35
2.6 Analysis of Matter Wave or de-Broglie Wave 36
2.7 Davisson and Germer Experiment 37
2.7.1 Experimental Setup 38
2.7.2 Method 38
2.7.3 Observations and Calculations 39
2.8 Bohr’s Quantization Condition 39
2.9 Phase Velocity and Group Velocity 41
2.9.1 Expression for Phase Velocity 41
2.9.2 Expression for Group Velocity 41
2.9.3 Relation between Phase Velocity (v ) and Group Velocity (v ) 43
p g
2.10 Phase Velocity of de-Broglie Waves 43
2.11 Heisenberg’s Uncertainty Principle 44
2.11.1 Physical Significance of Heisenberg’s Uncertainty Principle 45
2.11.2 Examples of Position-Momentum Uncertainty 46
2.11.3 Applications of Uncertainty Principle 48
2.12 Schrödinger Wave Equation 49
2.12.1 Time-Independent Schrödinger Wave Equation 49
2.12.2 Time-Dependent Schrödinger Wave Equation 50
2.12.3 Derivation of Time-Independent Equation from Time-Dependent Equation 50
2.13 Physical Interpretation of Wave Function y 51
2.14 Normalized Wave Function 51
2.15 Properties of Wave Function 52
2.16 Eigenvalues and Eigenfunctions 52
2.17 Applications of Schrödinger Wave Equations 52
2.17.1 Free Particle 52
2.17.2 Particle in One-Dimensional Infinitely Deep Potential Well (Or Particle in 1D Box) 53
2.18 Energy Eigenvalues 54
2.19 Eigenfunction (Normalization of Wave Function) 55
Solved Examples 56
Short Answers of Some Important Questions 60
Important Points and Formulas 61
Multiple Choice Questions 61
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contents • ix
Short Answer Type Questions 63
Long Answer Type Questions 63
Numerical Problems 63
Answers 64
Chapter 3 Wave Optics: Interference 65
Learning Objectives 65
3.1 Introduction 65
3.2 Interference of Light 65
3.3 Superposition 66
3.4 Types of Interference 66
3.5 Theory of Interference 66
3.5.1 Constructive Interference or Maxima 68
3.5.2 Destructive Interference or Minima 68
3.6 Coherent Sources 69
3.6.1 Condition for the Interference or Permanent or Sustained Interference 70
3.7 Fringe Width 70
3.7.1 Bright Fringe or Maxima 71
3.7.2 Dark Fringe or Minima 71
3.8 Interference in Thin Films 71
3.8.1 Interference in Thin Film Due to Reflected Light 71
3.8.2 Interference in Thin Film Due to Reflected Light 73
3.9 Colors of Thin Films 74
3.10 Interference in Thin Film Due to Wedge-Shaped or Thin Film Interference of
Increasing Thickness 74
3.10.1 Condition for Constructive Interference or Maximum Intensities
or Brightness 76
3.10.2 Condition for Destructive Interference or Minimum Intensities or Darkness 76
3.11 Fringe Width 76
3.12 Newton Rings 77
3.12.1 Experimental Arrangement 77
3.12.2 Newton’s Rings by Reflected Light 78
3.12.3 Condition for Constructive Interference or Maximum Intensities
or Brightness 78
3.12.4 Condition for Destructive Interference or Minimum Intensities or Darkness 78
3.12.5 Diameters of Dark and Bright Rings 79
3.12.6 Determination of Wavelength of Light Used 80
3.13 Determination of the Refractive Index of a Liquid 81
Solved Examples 81
Short Answers of Some Important Questions 85
Important Points and Formulas 85
Multiple Choice Questions 86
Short Answer Type Questions 87
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