IIT

If you become an IIT Graduate, you will get great respect. IITs have high quality classrooms, laboratories, computer centre, Wi-Fi enabled campus. The top benefit is job security. Faculty members are highly qualified and really supportive. Great infrastructure and a lot of extra-curriculum activities. The biggest benefit is that top companies and market giants like ONGC, Google, Microsoft, TCS, Asus, Snapdeals recruit the IITians.

Hi Shweta,
Hope you are doing good. Firstly congratulations for getting qualified in JEE Mains. According to me, scoring 35% is preferred.

Yes, you will get NIT but you can attempt for all the counselling.

Yes, sure! Why not!
If you can qualify JEE Advanced, then I am sure that you will definitely get a NIT. But be sure to score more than cut-off marks. Have self confidence and focus, just concentrate on your studies and don't waste the time.
Best of luck.

I think there is no "best" thing in studies. Only we are the one who makes everything better through our hard work and dedication. But as to answer your question, in my opinion, FIITJEE has the best faculty members all over India. here are the reasons:
1. The test series of FIITJEE is up to the level of real JEE Exam.
2. The modules of FIITJEE are designed in a good way.
3. They gave the best result.
4. They do not buy toppers.
5. They publish their actual result. There's a platform called StandYou which provides the platform to the students to search-compare-apply for more than 30000+ coaching in 120+cities on basis of 75+ data points.

Seats vary in every college and depend upon college to college. Please find the details regarding your query in below link
https://www.shiksha.com/architecture-planning/course/b-arch-indian-institute-of-technology-roorkee-8343
I cannot tell you about the all IIT you have to check on your own

Being an SC candidate, you need atleast 65% aggregate marks. It is 75% for general candidate.

Hi Vishnu,
You can use this link to find out your answer. Hope this will help:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=cconnect&utm_medium=CR_JEECP&utm_campaign=6375912.

Both IIT and IIM are different. You cannot appear for IIT exams without maths. Also IIM is for management course which can be taken by the student of any stream.
I am attaching a link for your answer:
https://www.google.co.in/amp/s/www.shiksha.com/mba/articles/amp/20-mba-entrance-exams-you-can-take-this-year-blogId-11473

It depends on your home state. For All of India, I would recommend VIT, SRM, KIIT, ITER, BIT, NSIT and many more. You can go to https://shiksha.com and find great colleges in your home state or any part of the country.
Good luck.