Hello..
If you want to get the admission in nits or IITs you should write the JEE mains and JEE advanced.For this you should get minimum of 75% marks in your local board.

If you want to get in the admission in bengal you should write wbjee which is conducted in your state.

For more details about the wbjee please visit the below link:.
https://www.careers360.com/exams/wbjee


All the best....

Hello aspirant....
On the basis of board marks you cannot get government engineering college.You have to qualify engineering entrance competitive exams like Jee mains,WB JEE,MHCET,KIIT, MPPET etc.A minimum percentage is required in12th board for applying the application form as per criteria given by exam conducting body.It is good to score more percentage in 12th board exam.It is useful for you.
Hope you get it.
Good luck.