JEE Main

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JEE Main paper 1 is GATE for JEE Advanced through which you can go to IITs, and mains score is only for entry in NITs, GFTIs, and other institutes. So, you have to crack JEE Advanced with a superb rank to get into IIT, Kharagpur.

Never pick a new topic in last 2-3 weeks, just strengthen your good topics as well as poor ones. Try to familiarize with the pressure of exam and one and most important you should have learned all formulas because in JEE Mains question are cracked by formulas (because speed matters) even if you have cracked the concept.

See, it totally depends on you. Really. Let's take my example, I had never studied like IIT in 11-12, but I have confident in me, because I know I had not studied properly and I can break it if I study well. So I take a drop and changed my city because that city was now highly distractful for me. And here I am (NIT-B). So it totally depends on you what you think from inside, Taking a drop in not a bad option if you are not happy with your marks and you think you can increase it more. If you get one more chance.

For Bachelor in Architecture, top entrance exams is given below:
NATA
JEE Main and Advanced
AMU Arch
KIITEE
IPUCET
COMEDK UGET
KCET
UPSEE
TANCET.

In Ramaiah Institute of Technology, if you go through KCET it is about 65 k and COMEDK is about INR. 2 lacs. Management depends upon the administration department. You can also try getting scholarship if you have any reservations.

I don't know about Satyabhama if giving scholarship on the basis of JEE. They provide admission by giving their entrance exam that is SAEEE. The application process is still going on. If you want admission in that college you can fill the form and score very good rank. Where you will have a fair chances of getting scholarship. Also, the top three in semesters is awarded a scholarship which is named as Remibai Jeppiar Scholarship

Yes, it is possible but you won't get very good colleges, you can also give private colleges entrances. Some colleges also give direct admission based on 12th score as well. Even some colleges are there where you can apply and they will definitely give admission. But, JEE is the prestigious exam to enter into the reputed colleges.
All the best.

JoSAA is only for government colleges and not private colleges. You have to apply for private engineering colleges separately. Many of the private colleges accept admission on the basis of JEE Mains but you have to apply separately.