Physics

As far as I know, the syllabus does include physics and mathematics in the entrance exam of Integrated M.Sc. B.Ed. in Chemistry (CUCET), please click this link to see details and all the subjects covered-
https://www.shiksha.com/science/cucet-exam-syllabus

There are three important criteria for getting admission in B.Sc physics:- 1) you must have maths and physics as your compulsory subject in your +2. 2) you must score minimum 60% in aggregate of best of 4, which should include maths and physics and any other 2, so that you can be eligible for admission. 3) You must score minimum of 60% in physics. There isn't any entrance exam for B.Sc in physics. But as per past record, the cut off stands at 90%+. Try to keep your marks high in maths and physics. 

You can not apply for M.Sc. Physics, because the B.Sc. Physics is required for M.Sc. Physics programme.

To get into the field of aviation you need to have physics as a compulsory subject.

Yes, you are. Criteria- you should to be graduate from a recognised college with a minimum cutoff percentage stated by respective college or university and preferably in Science stream. However, it was better if you would have specified the college you needed.

To become a theoretical physicist, first you need to earn a Bachelor's Degree in Physics. Then gain some research experience, clear the additional tests, and earn a Doctoral Degree, and finally, brighten your career by joining postdoctoral research projects. You should have the skills to design experiments and to think outside the box.

There are either public national universities or private universities in US. MS Physics, yes it can be found in majority of universities. Check out the list of national/public universities here and visit their websites for specific instructions-
https://www.usnews.com/education/best-colleges/slideshows/explore-the-10-top-public-national-universities.

In the present times, cut-offs are sky rocketing. KMC asks for minimum 92 for admission in Zoology via General Category. Also, as you are asking about Computer Science, which is offered in very few colleges in DU, one can't be sure to have a seat sure shot with that percentage especially via General Category but then hope it is which keeps us going. Best of luck :)

Yes, you are eligible. Just see the seats and admission procedure of the college.
All the best.

Please mention the course you want to pursue for better assistance
Follow the link below for details :
https://www.shiksha.com/university/cochin-university-of-science-and-technology-Kochi-28013.