CBSE 12th

Hello Suraj,
Some of the best colleges for Music in the world today are Berklee College of Music, The Royal Academy of Music etc. Here are some more: http://www.onlineschoolscenter.com/posts/20-prestigious-music-degree-programs-world/
Visit websites of the colleges to know about the application process.

Hello Rahul,
Take your SAT or ACT and ace the exam. The application procedure is through the common app portal. Please note the university in question is one of the top most in the world and only scores won't be enough. Browse though the website and prepare. Take a look here:
https://college.harvard.edu/admissions/apply

Hi,
The best colleges for your course are:
CMC (Christian Medical College)
JIPMER
JSS University
According to me, JIPMER is the best because of ranking, less fee structure and the medical facility.
I hope you got your answer.

Yes, absolutely if you are unperformed or failed in any of your exams, CBSE offers another chance to all students to better their results.

It depends on what you have taken in your PUC. If you have taken NEET then you can for doctor courses. If you have taken engineering you have plenty of options like ECE, EEE, civil, CSE, mechanical, etc.

You can go for DMLT, X-ray technician, D.Pharma or nursing after 12th with biology.

For vast knowledge Trueman is good. I am using Trueman and Pradeep both for teaching. I have found that Trueman is slightly better than Pradeep.

There are many institutes and organisations offering courses in robotics which can be pursued after you complete your 10+2 studies. Please refer to the link mentioned below for eligibility and scope of taking up a career in Robotics:
https://www.shiksha.com/b-tech/articles/your-career-after-robotics-blogId-4610

Even if you haven't opted for maths in higher secondary you can take BCA as your grad but, in most of the cases, maths is one of the two general papers for BCA in college. So, it would be better if you choose a college and find out their general subjects with BCA. Grad level maths is a bit tough but not for those who have studied it in HS.