This book is a part of a series of six books written to provide complete coverage of the NCERT Science syllabus for classes 9 and L0 prescribed by the Central Board of Secondary Education (CBSE). The six books in this series are: Science for ninth Class (part- L): Physics, Science for ninth Class Part-2): Chemistry Science for ninth Class (Part-3): Biology; Science for tenth Class (part- L): Physics, Science for tenth Class (Part-2): Chemistry and Science for tenth Class (Part-3): Biology. The most important feature of the revised editions of these books is that a large variety of solved and unsolved questions has been included to assess the learning abilities of the students. The main aim of bringing out this series is to make science more attractive, interesting and understandable to the students.

The authors feel delighted to bring out the Twenty first thoroughly revised edition of this book. The present edition is strictly according to the latest syllabus and question paper design issued by the C.B.S.E. for the academic session 2026 - 2027. The salient features of this edition are : 1. As per the latest question paper design, Competency Based Questions have been appended at the end of each chapter which include Multiple Choice Questions, Very Short Answer Questions, Assertion Reason Based Questions and Case Study Based Questions. 2. Higher Order Thinking Skill (HOTS) based examples and questions have been added at the end of each chapter. 3. Mind Map and Chapter Test of each chapter have been incorporated in this edition. 4. All the questions of latest CBSE Question Papers and the Latest Sample Paper (Basic and Standard) issued by CBSE have been included in this edition. 5. A separate NCERT CORNER is given at the end of each chapter which contains all the examples and exercises of the latest NCERT Text Book along with Hints and Answers. 6. All the questions of NCERT EXEMPLAR PROBLEMS have been incorporated in this edition.