Engineering

Yes according to sources, they have a consistent and growing placement track record. Top companies for the placement are Acara solution India and Adecco India pvt Ltd.

You can consider following:
IIT Bombay IIT Roorkee in India
Massachusetts Institute of Technology and Stanford University abroad.

Diploma in Petroleum Engineering is a course designed to create professionals with specialized knowledge of techniques and procedures followed in a gas or petroleum industry.
There are nearly 140 petroleum engineering colleges in India, out of these 75% are private colleges and 25% are government colleges.
Good colleges are
IIT Bombay
RGIPT Amethi
IIT Dhanbad
IIT Madras
IIT Kharagpur

No it's not at all difficult. Keep 3 things in mind.
1)Attend classes to get notes and topic which the professor stressed upon in classes
2)Practice 5 years PYQ in class tests and before sem
3)atleast revise 3 times and practice by writing.

It's depends on the state in which you presides. Having 90 percent can lead you to gold colleges in your state where they consider JEE Mains marks. If you are from general category it's a little difficult but if you are from ews or OBC or SC then you can get a good NIT or gfti so apply for them in JoSAA counseling.

Yes you can try. For ST category, you will need to score at least 100 to 130 in JEE Mains exam.

You will definitely get JEE Main rank as you have submitted form as an appearing candidate. The only problem you will face is at the time of admission and verification to that definite college where you can get disqualified if you have not 75 percent.

No as of now the portal has not opened again for new form submission for session 2.

SC Certificate is valid all across India. So if you have issued it from any state you can show it as an authentic proof for verification anywhere in India.

Oriental University
Galgottias University
Government Polytechnic
Nagpur
Guru Gobind Singh Polytechnic - Nashik
Savitribai Phule Pune University
Pune
C. V. Raman Global University
Bhubaneswar
Savitribai Phule Pune University
Pune.