We are glad and excited to announce that the Second Edition of this book received an overwhelming response fromthe engineering student community, compelling us to release its Third Edition within a very short period of time.This thoroughly revised Third Edition has been updated with additional matter, many solved problems, includingsolutions to All University Examination Problems and Numerous Exercises for Practice. Also we have included UniversityQuestion Papers from Dec. 2012 to May 2018.Special care has been taken to maintain high degree of accuracy in the theory and numericals throughout the book.