Hi, here are some of the recommended books for BTech Engineering Physics:

1.Applied Physics by A.K JHA. Its really good and easy to understand

2.Fundamentals of Optics by D.R. Khanna and H.R. Gulati.

3. Introduction to Special Relativity by R. Resnick

Hope this helps! Go for the first one if you want an easy to understand and simple book, but focus on making your own notes as they are absolutely essential as well.

Hope this helps!