This book is specially designed for B.E. and B.Tech. students of all branches of engineering and technology. Efforts have been made to explain the fundamental concepts in simple but comprehensive manner so that B.Sc. Pass and Honours students can use this book as a reference. The unique strength of this book is the mathematical and scientific approach. Mathematical problems and model questions, including multiple-choice questions, short-answer-type questions and long-answer-type questions, are provided in Appendix II of this book as exercise for students.