This book is intended partly to serve as a textbook cum reference for the course Engineering Physics taught at the undergraduate level in engineering colleges all over the country. The other purpose of the book is to serve as a reference book for research workers in theoretical physics and signal processing. Engineering physics or engineering science refers to the study of the combined disciplines of physics, mathematics and engineering, particularly computer, nuclear, electrical, electronic, materials or mechanical engineering. By focusing on the scientific method as a rigorous basis, it seeks ways to apply, design, and develop new solutions in engineering. The whole syllabus comprises various branches of physics considering various engineering applications in day to day life. It starts with optics which is being divided into Interference, Diffraction and Polarization. In these topics generally light interaction with various matters and matters effect on light character has been discussed. In Interference, nature of light has been studied with various optical devices. Various phenomenon based on Interference of light has been explained. The subject matter in this book has been introduced in a very lucid style so that the students may find it interesting. There is profusion of illustrative examples of variety everywhere in the book.