B.Sc Physics

Yes, Labish, you can pursue B.Sc. in applied Physics and B.Sc. in robotics engineering at the same time because UGC has officially made dual degree legal in India. But there is one thing that the courses you are talking of both demands a lot of time and dedication. Lab work hours will be there in both courses. It might become difficult for you to manage both the courses simultaneously. You can do one thing that, take admission into that college which provides Physics as a optional subject in B.Sc. in robotics engineering.

Yes, Payal you can pursue a master's in Physics Course even though you have B.Sc. In forensic degree. For that purpose, you must have studied Physics as a subject at least for four semesters during your Bachelor's degree programme. Along with that, you must maintain a minimum of 60 percent in B.Sc. Degree. It is all that you need.

Deen Dayal Upadhyay College is better among all the colleges that you have mentioned.
I recommend to see NIRF ranking of colleges before taking admission.

You can check out the following for more information - https://www.shiksha.com/college/iit-madras-indian-institute-of-technology-adyar-chennai-3031.

Top Astrophysics Colleges in India
Indian Institute of Science, Bangalore. Indian Institute of Astrophysics, Bangalore. Physics Research Laboratory, Gujarat. Tata Institute of Fundamental Research (TIFR)
Aryabhatta Research Institute of Observational Sciences (ARIES), Uttarakhand.

You do not need to take an entrance exam to enter into LPU's M.Sc. Programme; the Eligibility Criteria (Qualifying Exam) is a Bachelor's degree (any subject) or equivalent with a minimum of 50% aggregate marks. If you wanna avail the opportunity of scholarship From LPU than give LPU NEST test
Hope this helpful!

Yes, it is a good University.

Yes you can do Maths in first year and then choose whatever subject you want after that

All are different.

Dear Student,
You asked about Belur vidya mandir which is actually Ramakrishna Mission Vidyamandir. The first thing it does not offer BSc in Chemistry or industrial chemistry and second if you are asking about B.Sc. (Hons.) in Physics, then you can check the below link for further details.
https://www.shiksha.com/college/ramakrishna-mission-vidyamandira-howrah-52978/courses/bsc-bc