Students aspiring for a career in Engineering and/or medical sciences need to develop a clear understanding of fundamental concepts and problem-solving skills. Cengage foundation Series for Physics, Chemistry, Mathematics and Biology for Class IX and X is aimed at helping students achieve these objectives. The books in this series have been written by eminent teachers who have used their rich experience of teaching high school students while developing these books. Each book in this series is organized in a logical sequence to help students learning for a strong foundation in the subject. The theory and problems are aligned to the curriculum suggested by various High school boards and these books also deal with some additional topics aimed at preparing students for the entrance examinations. This series should help in building a strong foundation among students preparing for various engineering and medical entrance examinations and shall bring out the best in them.