what are the exams will this college will accept? because they have given only gate is accepted

You can get into IIST (Indian Institute of Space Science and Technology) for their Undergraduate programmes. The admission is based on JEE Advanced scores. Which means you need to have studied Physics, Chemistry and Mathematics in 10+2. You can pick any of their 4 year Bachelor programmes like B.Tech in Physical Sciences, B.Tech in Avionics and B.Tech in Aerospace Engineering, etc. Or you can also pick up their 5 year Integrated courses in Master of Science in Astronomy and AstroPhysics, Master of Technology in Earth System Science, Master of Science in Solid State Physics and Master of Science in Optical Engineering, etc.

IIST also offers Postgraduate Programmes like:
M.Tech in Soft Computing & Machine Learning
M.Tech in RF & Microwave Engineering
M.Tech in Geo informatics
M.Tech in Optical Engineering
M.Tech in Machine Learning & Computing
M.Tech in Solid State Technology
M.Tech in VLSI & Microsystems
M.Tech in Materials Science & Technology, etc. and admission to all these courses is through GATE score only. Please check our page for more information: https://engineering.careers360.com/articles/iist-mtech-admission