IIT

No, in over all 12 class, you must scored the 75% in 12. And you must have the PCM as your main stream for getting the admission into IIT, IIIT, etc. These are the above two conditions for admission.
Best of luck.

You can go for any other state level government college through state level entrance exam like UPSEE, WBJEE, etc. You can go for BITS through BITSAT exam. Or you can go private college like KIIT, VIT, SRM, UPES, ICFAI, etc. You can also get admission on basis of 12 percentage. If you have score more than 85 or 80 +% then you may get the government college if you have qualified the JEE main. Private college, also direct admission on basis of 12 percentage
Best of luck.

Some of the colleges have their personal admission test exam like BITSAT. Also, in some of the colleges, you can get admission on the basis of your JEE Mains marks or your class 12th mark.

Yes, you will get good engineering colleges in your locality or in your state. Try JEE college predictor to get more information and insight about college & branch which you can get on the basis of your rank-
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=connect&utm_medium=CR_JEECP&utm_campaign=4067795.

The pay grade in NDA is according to the government norms which government give to the officers but with good pay scale, you get respect and chance to serve the country if you only want good pay then you have to choose IIT because their package is very high as compared to the officers in defence.

Hello Piyush,
I am attaching a link for your query please go through it:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor?utm_source=connect&utm_medium=CR_JEECP&utm_campaign=7576872
Good luck.

If you want to study in IIT then you have to quantify JEE Mains and JEE advance for undergraduate B.Tech courses and GATE exam for M.Tech courses. If you want to study in IIM then you have to clear CAT exam with good marks.

If you want to do MBA from IIM or IIT, you need to complete your graduation and than you need to give CAT exam and need to score more than 97 percentile in CAT than only you can get chance yo get admission in IIM or IIT.