on the contents of the Science Textbook for Class X published by the Council in December, 2006.
The main objective of the book on Exemplar Problems in Science is to provide the teachers and students a large number of quality problems in various forms and format with varying levels of difficulty to facilitate teachinglearning of concepts in Science that are presented through the textbook for Class X. It is envisaged that the problems included in this book would help the teachers to design tasks to assess effectiveness of their preparation of balanced question papers for unit and terminal tests. The feedback based on the analysis of students responses may help the teachers in further improving the quality of classroom instructions. In addition, the problems given in this book are also expected to help the teachers to perceive the basic characteristics of good quality questions and motivate them to frame similar problems on their own. Students can benefit themselves by attempting the problems given in the book for self assessment and also in mastering the basic techniques of problem solving. Some of the problems given in the book are expected to challenge the students understanding of Science concepts and to apply them in new situations.
The problems included in this book were developed in workshop mode organised by the DESM involving practicing teachers, subject experts from universities and institutes of higher learning and the members of the Science group of the DESM whose names appear separately. I gratefully acknowledge their efforts and thank them for their valuable contribution in our endeavour to provide good quality instructional material for the school system. I especially thank Professor Krishna Kumar, Director, and Professor G. Ravindra, Joint Director, NCERT for their administrative support and keen interest in the development of the book. I acknowledge with thanks the dedicated efforts and valuable contribution of Dr. Anjni Koul, coordinator of this programme.
I also thank Dr. K.T. Chitralekha, Copy Editor and Shri Mohammad Jabir Hussain, DTP Operator for typing the manuscript and preparing a press-ready copy. We look forward to feedback from students, teachers and parents for further improvement of the contents of the book. Dr. Hukum Singh New Delhi
Professor and Head
DEVELOPMENT TEAM MEMBERS Rupamanjari Ghosh, Professor and Dean, School of Physical Sciences, Jawaharlal Nehru University, New Delhi. Chief Advisor of Science Textbooks for Classes IX and X Alka Mehrotra, Reader, DESM, NCERT, New Delhi
tt o N be C