Hey Bhagyashree!

You haven't mentioned the exam for which the questions will be based on 11th and 12th class level in physics, chemistry and biology. Is there any particular entrance exam for which you are referring to? Since you haven't mentioned the exam name, I will tell you the general basis of questions. Questions which are asked in the competitive exams are generally based on 11th and 12th concepts and topics but the level is much hard as compared to school level. From the same concepts, intricate questions are prepared. You should first go through the syllabus of the exam and match it with your school concepts.