B.Tech Scope

Dear aspirant,
You can see yourself anywhere depending upon your taste and inclination. You can do MSc from prestigious Universities like IARI, PAU, GBPUAT and other. You can apply for Management from MANAGE or IRMA and other. You can apply for joint biotechnology exam conducted by JNU. Or you can also apply for private companies and get absorbed there. Choices are limitless. You have to decide.
Agriculture is the one of the most unexploited sector in India and it has a lot of opportunities to offer. (Remember profit is a reward for those who serve the society.)
Identify those opportunities and start finding ideas to exploit them.
Hope it helps.

Yes in some institutes and No in some institutes, it's possible to study M.Sc. In Physics after B.Tech in Mechanical Engineering. But only few colleges are giving chance for B.Tech students like Delhi University. Do some research about colleges giving this chance and join accordingly.
You would only be accepted to a few institutions if you wanted to pursue an MSc in physics. Traditional universities will not even accept you for a master's degree in physics. Furthermore, btech mechanical engineering is solely based on basic classical mechanics or lower level classical mechanics, the majority of which is newtonian mechanics.
BSc physics is focused on quantum mechanics, and almost all areas of study in BSc physics use quantum mechanics like there isn't any newtonian mechanics in the universe, so whatever they would be thinking in India about degree equivalence, a BSc physics is way higher than a btech mechanical engineering in terms of theoretical knowledge and depth of physics and mathematics, in fact, a BSc physics is way higher than btech, So, if you get into one of those select few universities, you'll have to work extremely hard or you'll end up in hell. Also, if you want to study physics overseas, a btech is ineligible for an MSc or MS in physics. Only those with a BSc/BS in physics are eligible. As a result, you won't be able to pursue an MSc in another country because their qualifying standards only allow for BSc/BS physics.

You can do Masters in psychology being a B.Tech CSE graduate. It's quite easier to switch now to Masters psychology. Get ready to do hardwork since you are not a psychology background student. Few colleges won't allow non psychology background students, check before and join accordingly!
Without a bachelor's degree in psychology, you can pursue an MA or MSc in psychology. The eligibility requirements will differ from one university to the other. Many leading colleges provide an MA in Psychology to graduates with a 50 percent graduation rate. So, if you have a B.Tech with a grade point average of greater than 50%, you can apply.
Some colleges grant admission to courses based on their degree grades, while others grant admission based on their entrance exam rank. In addition to the written test, some universities will conduct an oral examination. Almost all major institutions offer this subject, which you may research on the university's website.

Without a doubt, MBA is a very good notion after B.Tech. Job opportunities after MBA in India are wide, and it is the responsibility of the students to pick up the right job from the options available. Mittal School of Business is among the first 10 institutions in India to get ACBSP (USA) accreditation, Mittal school of Business ranked among the top 40 Management institution in India, as per NIRF ranking 2021. The curriculum is made keeping in mind the current market trends. The placements are 100%, and students have special placement-oriented classes that serve as a booster for students to clear the exam and interview. Companies like Hyatt, Ritz Carlton, Adani Wilmar, Altruist, Al-Rakha, Dharam Consultancy selected LPU students for International locations. The highest package availed is 21 LPA. More than 650 companies visit LPU every year for recruitment with an average of 5-12 LPA packages and the highest package was 21LPA. Every year visiting companies escalate in number and till date University has recorded the highest placements in North India.