This textbook has been specifically developed on the directives of National Education Policy (NEP 2020) and is as per latest curriculum of B. Sc. Physics (Fifth Semester) for the Universities of Uttar Pradesh. This book comprises of two parts: Part A deals with Operator formalism, Eigen & Expectation values, Uncertainty principle, Schr?dinger Equation, Applications of Schr?dinger Equation and Part B deals with Vector Atomic Model, Spectra of Aalkali and Aalkaline Elements, X-rays and X-ray Spectra and Molecular Spectra. Maximum number of Laboratory experiments are incorporated in Practical paper. These experiments are mostly on Dispersive power of Prism, Specific rotation of sugar solution by Polarimeter and wavelength of Laser beam by diffraction due to single slit experiment. All topics are lucidly explained in this book.