Modern Physics is a comprehensive and accessible book in accordance with the latest revised syllabus prescribed by the UGC for B.Sc. (Pass and Hons.). It provides a thorough understanding of the subject with the help of concepts, mathematical derivations, applications and a good number of worked-out problems, short-answer questions, objective-type questions and exercises. The text of the book is a detailed and systematic presentation of a wide range of topics — atomic, molecular spectroscopy, quantum mechanics, statistical physics, solid state physics, lasers, optical fibres, semiconductors, superconductors, general relativity, nano materials, atomic nucleus, etc. The text is updated with all recent and relevant advances. The book is eminently suitable as a textbook for B.Sc. (Pass and Hons.) and also useful for M.Sc., B.Tech., UGC-CSIR (NET-SLET), GATE and other competitive and entrance examinations.