B.Sc Physics

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.

LPU Curates two programs in Game Design
1. B.Design - Gaming 4 years
2. B.Sc Design - 3 years
The specialization comes with an option of disciplinary minors as a set of four elective courses in a related area to develop a competency beyond the major area, these are:
3D VISUALIZATION
ANIMATION
CONCEPTUAL DESIGN
EFFECTS AND SIMULATION
GRAPHICS
There is a big focus on Industry Interface:
Tie-ups with industry
Content delivery by industry experts
Projects in collaboration with industry
Internships to engage deeply in hands-on real-life situations

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.

Top B.Sc. In Physics Universities in India 2022
SRM University Chennai - SRM Institute of Science and Technology. IISc Bangalore - Indian Institute of Science. Sathyabama University - Sathyabama Institute of Science and Technology. Gandhigram Rural Institute, Dindigul. Shiv Nadar University, Greater Noida. Banaras Hindu University
St Stephen's College, Hindu college. Miranda house
Hope it helps.

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.