B.Tech Eligibility

Hello there,
You need above 55% in PCM for BE or B.Tech. Try for private institute.
Regards
Lalit kumar.

Yes, you are eligible to do B.Tech, but you must have a Diploma in mechanical engineering.

Amity University, Gwalior is a private university located in Madhya Pradesh. It is accredited Grade A by the NAAC. Amity Gwalior offers B.Tech course in total 9 specializations. The candidates who are willing to apply for this course must have scored at least 60% in Chemistry, Math, Physics, and English combined in 10+2.
The eligible candidates can apply for Amity JEE exam. The selection of the candidate would be done on the basis of the score obtained by the candidate. The will followed by a test on the day of the interview.
Direct admission is also done on the basis of a valid score in JEE Main.

You have passed 10+2. This is the foremost condition for getting admission in any graduation course and that's why you can definitely get admission. Good luck.

https://www.google.co.in/url?sa=t&source=web&rct=j&url=https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor&ved=2ahUKEwiz1-Ckk7TbAhXLq48KHUJKCFQQFjAAegQICRAB&usg=AOvVaw1N9BzFtyUCP4JU-2UQHQ0H
Use the link shared above for all over India.

There is no such policy. It is on a merit basis and as per different rounds of counselling. The first counselling normally calls upto 600 rank. Then in the second and third counselling, all ranks are invited. Once the seats are full, the counselling stops. So there is no defined cutoff rank. It is as per attendance of candidates during counselling.

Yes, you're eligible, though you won't get any decent government college. Try to get some good private college.
Moreover, you can predict the college you can get with your rank with this predictor-
https://www.shiksha.com/b-tech/resources/wbjee-college-predictor
All the best.