B.Tech

Please refer to the link mentioned below for the list of colleges which offer M.Sc through correspondence or distance:
https://www.shiksha.com/science/colleges/distance-correspondence-m-sc-colleges-india

Yes, you can. Start preparing for CAT exam.

Please elaborate your question and mention the domain in which you to pursue the course.

If you are good in programming and wants to learn, go with CSE or if you are interested in electronics, go with ECE. Similarly, if you want to learn about mechanisms of different engines, go with mechanical engineering.

Percentile is measured on the basis of highest marks in the examination. Suppose the highest marks out of 100 is 80 so the person who scored 80 has achieved 100 percentile.
Hence top 20 percentile means students falling in the range of top 20% scorers.

Your rank in UPTU is good. I would recommend that you should participate in the counselling process and take admission in a good college.

To pursue MS from a foreign university, you would first need to clear your backlogs, unless mentioned otherwise. Your work experience and scores in GRE are fine.

According to me, there is no difference on BE and B.Tech. I can assure you that the courses are same in both of them. Difficulty level depends on the university and on the marking scheme.
Apart from this, practicals are there in the course but college fails to provide practical knowledge. A few insti