This book is written on the basis of the syllabi of all major Indian and other universities. The "Modern Physics-Volume-1" includes X-Ray's, Laser, Nanotechnology, Nanomaterials, Biophysics and Bioinstruments. Highest priority has been given on clarity of the subjects and conciseness of topics. For lucid presentation of the concepts and the principles, the book has been well-illustrated with self-explanatory diagrams. A large number of typical worked-out problems have been given at the end of each chapter. Many essay type, short answer-type questions and numerical problems including those appeared to different university examinations are given as exercise in each chapter.