Engineering Entrance Exam

No, as the admissions in NSEC are through JOSAA counselling and you don't stand eligible for it as you have not given JEE Mains. You should now left to go for private universities having their own entrance exams.

Hi Karan,
Firstly, It depends upon the cutoff marks for your shortlisting in these branches. To get an idea, please go through this link:
http://www.bitsadmission.com/cutoffscores2017.aspx
For the understanding of the difference, between the two branches, both have origin in Electrical Engineering. But

I suggest you go to the website of Cochin University of Science and Technology and download the B.Tech last rank 2016, if you are having trouble understanding the code they have used and it's implications, let me explain it to you
Eg code: BTCS1F stands BT-B.Tech CS -computer Science 1-main campus F-

No, but if you want to study in any other Techno India Group college, then you can visit the main branch and have a talk with them.

Yes, but visit TIU campus once. TIU is good but Makaut cllgs are more valued. Try Msit , Netaji subhas, TICT or any other Techno India college from Makaut.

No, only your JEE Mains Rank is considered for admission to JIIT Noida.

It conducts its own individual exam for its M.tech programme called PGEE. You can apply for it
Thanks.