IIT

Since you are interested in coding and want to learn computer skills Ism dhanbad case course will be good option for you.

Hello,
Please use Shiksha's predictor to find a good college:
https://www.google.co.in/url?url=https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor&rct=j&sa=U&ved=2ahUKEwi7xLvrj4DcAhVEvo8KHX1bB0QQFjAAegQIARAB&q=sissha+college+predictor&usg=AOvVaw2XP_zVyb0ocLS8jQERCtIp

You can look for SRM University, Lovely Professional University and Amity University.

Hello Adrija, One can join teaching profession in a college after PG in a subject. However Ph.D. is now being increasingly sought. I would advise you to have a look at the concerned webpage of UGC for details of the latest circular on the subject.

Please follow Arihant. This book is named as RD Sharma objective for IIT-JEE mathematics.

Yes, you can get any IIIT or IIT if your rank is in general category. However, for confirmation you can check the link below:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor

After the completion of all 7 rounds of counselling the dates will be provided on the official website of the institute. You have to visit during these dates for the registration purpose.

After accepting the seat and visiting the reporting center the seat will be allotted to you. After completion of all the 7 rounds of JOSAA counselling you have to visit the official website of the respective institute for the dates of registration. You have to visit the institute during these dates for registration purpose.

You need to score a minimum of 75% in HSC.

Here I suggest you a site for your question
https://www.quora.com/Are-there-any-IIT-institutes-for-astronomy-astrophysics.