It has been designed both as a help book as well as a textbook. It has been written in a lucid stle and simple language. Each chapter begins with a brief summary indicating basic concepts/important terms and formulae used. The portion "Main Course Content" deals with the syllabus systematically and topicwise. In each chapter short and long questions are arranged to facilitate understanding of the subject easily. Each section deals with problems related to particular physical principle. The unsolved problems in the exercise have also been classified in the paralle manner.