You're looking for a reliable PDF resource on nuclear physics by A.B. Gupta. Here's some information to help you:
If you are looking for deeper conceptual understanding or more rigorous theory, some reviewers suggest opting for texts by S.N. Ghoshal or other specialized authors. However, for a student focusing on passing B.Sc. (Physics) exams with practical problem-solving skills, Gupta's book remains a popular and "superb" recommendation. Modern Atomic and Nuclear Physics - Amazon.in
To obtain a legitimate copy, you can purchase the physical textbook directly from the publisher at Books & Allied
Nuclear Models: Detailed explanations of the Liquid Drop Model and Shell Model.