IIT

Dear Biswajeet,
No, it's not a good choice to do M.Tech in steel technology. After doing this course, there will be limited opportunities. You should choose either thermal engineering, design stream, manufacturing or precision engineering stream. There is more demand of this. Otherwise, choice is yours.

Hello Adarsh,
Yes, you are eligible to take admission in IIT after completion of the diploma. The diploma is considered as equivalent to 12th and hence you can get admission provided you fulfil all other conditions.

MCA is offered at IIT Roorkee only. The admission to the course is done on the basis of an entrance exam IIT-JAM which is conducted by IITs for admission in post graduate degrees in Science subjects.

You may refer to following link for JEE Mains 2017 syllabus:
https://jeemain.nic.in/WebInfo/Handler/FileHandler.ashx?i=File&ii=59&iii=Y

Yes, you will surely get admission into IIT. Admission into IIT goes upto 11000 rank holders.
Don't worry.

Diploma holders are eligible to appear in JEE (Advanced), therefore, they can apply to appear in JEE Main but rank and score of such students for JEE (Main) is not declared as diploma holders cannot apply for admission in NITs and CFTIs through JEE (Main) channel.

The annual fees at IIT is Rs.2 lakhs.

Hello Shiwang,
Automobile design is a very esoteric topic. Italian designers are most sought after. Many of them are students of fine arts and look from aesthetic point of view. Others are doing research in IC engines some are doing research in hybrid tech. I would suggest you do graduation in mechanical, then you can pursue M.Tech in machine design.