I am assuming that you are talking about the exams that a study needs to take for joining plus 2 in CBSE/ISC board. In case you are looking forward to opt for science stream then be thorough with your class 10 syllabus of Physics, Chemistry, Biology and Mathematics syllabus. To be on a safer side you read the 10th standard books of CBSE/ISC board of the above mentioned subjects depending on the board which you are going choose. Lastly as far as English is concerned you might have to write an essay so consider looking up for daily affairs, it might help you.