"The present edition of the book has been thoroughly revised and enlarged. Many new topics have been included in the text. The subject matter is divided into twelve chapters. Each chapter is self-contained and is treated in a comprehensive way, using the S.I. system of units. Harmonic Oscillators, Linearity and Superposition Principle, Oscillations with One Degree of Freedom, Resonance and Sharpness of Resonance, Quality Factor, Doppler Effect in Sound and Light, Medical Applications of Ultrasonics, Accoustic Intensity, Accoustic Mesurements, Wave Velocity and Group Velocity, Maxwell???s Equations, Propagation of Electromagnetic Waves in Isotropic Media, De Broglie Waves, Hersenburg???s Uncertainty Principle and Special Theory of Relatively are some of the important topics which have been given special attention. Solved numerical problems (in S.I. units), wherever necessary, are given in the text and the in the exercises at the end of each chapter. In this edition many new solved numerical examples of important topics have also been included so as to provide better understanding and practice to the students. The book is intended to be a textbook for the undergraduate students of Indian Universities."