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

Note that IIST is among the premier academic institutions in the country apart from the IITs that take admissions to its undergraduate B. Tech courses through the JEE Advanced window. So, obviously the level of input you should put into your JEE preparation should be quite high. 

Please refer to this Careers360 article for more information about the cutoffs:

• https://engineering.careers360.com/articles/iist-btech-cutoff

Also, please see here:

• https://engineering.careers360.com/articles/iist-btech-rank-list

Hope this helps you and all the best!