Some of the useful Physics text books you can read for GCE Advanced Level A/L are given here. There are other posts here on this web site on free text books published by educational publications department, English medium text books on Physics and books for school children on other subjects: Biology, Chemistry.
Dr P Geekiyanage, Senior Lecturer at Department of Physics, University of Sri Jayewardenepura has written several popular excellent question books and theory books.
Question books 1 MCQs and structured essay, 2 Essay questions, 3 Physics Revision
Theory books on 1 Measurements, 2 Mechanics, 3. Oscillations and Waves, 4. Light, 5 Heat, 6 Gravitational Field, 7 Electrostatics, 8 Current Electricity, 9 Electromagnetism
Books by Dr S D Rosa, Senior Lecturer at Department of Physics, University of Colombo, has written several books based on GCE A/L past paper questions and analyzed in simple language, how to solve those sums.
Dr Rosa has published several Past paper and question analysis books for each year from 2006. He also has published anther book which contains Past Papers from 1994- 2005.
Books by Y M P Yapa
MCQ books on Mechanics and Properties of Matter
Books by Prof. B.S.B. Karunaratne, University of Peradeniya
Light, Oscillations and Waves 1 and 2
Books by Prof. Lakshman Dissanayake, University of Peradeniya
Books on 1 Mechanics, 2 Matter and Radiation, 3 Heat, 4 Properties of Matter, 5 Current Electricity, 6 Fields, 7 Electronics.