CBSE

You can get the list of B.Sc. Entrance exam here:. https://www.shiksha.com/science/articles/top-bsc-msc-entrance-exams-in-india-blogId-13484 , You can check more exams on university websites.
You can take up M.Sc. And Ph.D. after completing B.Sc. And taking IIT JAM exam.

Nothing. Do not worry. I too had the same case. Go and meet your state board college and tell any teacher about direct admission in class 12t. They will conform your admission and that's how you can save your one yea. I am doing the same right now.

Pick up the board in which he is clear pass in all subjects and have attained good marks.

Colleges in India follow same pattern for admission. Either PCB or PCM percentage in aggregate is considered generally. It depends on choice of field you want to take up further. Foreign colleges, add up English language too.

Hi Aniket,
You are good at maths, but still failed. Quite surprising and no, without a strong mathematical background, you cannot possibly study what you want. You should consider retaking the exam and improve your scores significantly to be accepted by universities abroad. If you are really into astronomy I will suggest you take online courses a MOOC. This may help to further advance your studies.

If you have got very good marks in all other subjects, then grace marks up-to 8 is can be given to the student not more than that.

Interested candidates can apply directly to the college. Basic eligibility to pursue this course is that Candidate must have passed 10+2 from any recognized board. Regards.

BCA will be a better option if you are interested to make your career in IT industry.