Hello Laxman Sindhi. Thanks for contacting Careers360 and we hope we will be able to answer your query.

According to me, there is no fixed syllabus for the IISER aptitude test. It is of higher level than JEE Mains but a little lower than Advanced, speaking from my experience.

I would like to direct your attention to these Quora questions for more information:

• https://www.quora.com/in/Is-the-IISER-aptitude-test-as-difficult-as-the-JEE-Advanced
• https://www.quora.com/What-books-should-one-refer-to-to-crack-the-IISER-aptitude-test

Also I hope this will help you:

• https://www.shiksha.com/science/exams/amp/iiser-entrance-exam

All the best!