Sai, IIIT H conducts REAP (Research Aptitude Test) for 120 minutes. The exam is based on 11th and 12th syllabus of Physics, Chemistry and Mathematics. This is both for CBSE and most State Syllabus. REAP will emphasize on testing critical and creative thinking abilities of the Candidate. You can check the sample questions at: https://cdn.iiit.ac.in/cdn/www.iiit.ac.in/files/iiit/Section2-REAP-Sample.pdf

Your first go to books should be NCERT Books to get the basics right. And there are no specific books for REAP section. But you can prepare the same books that you have prepared JEE Mains for but at a more advanced level.