JEE Advanced

Yes, what Sohan Kumar said is right. I want to add some extra information.
JEE Mains has total of 90 questions each carrying 4 marks.
Total-360 marks
And there's negative marking also 1/4 negative for 1 wrong answer.

To get a top college and your desired branch you need to have a rank below 2000 if you are an OC candidate. The score can't be told exactly because the pattern and marking system differs every year. So, you need to have minimum 40%.

From this year onwards, class 12th results do not have any weight-age in JEE Mains and Advanced exam, but you need to score a minimum of 75% if you belong to general or OBC category. It is required to get admission in IITs and NITs.

IIT and NITs are not the only good institutes for engineering, there are multiple other good options. If your JEE Mains score is not good you can still get admission in a good engineering college. In order to mitigate risk of failure in JEE, you are advised to appear for some other engineering entrance examinations.

Yes, you have to score approximately above 75% in class 12th exam to be eligible for JEE advance.

Hi,
You have to qualify JEE Mains and Advance. If you get above 120 marks in JEE Advance, then you can get admission in IIT.
Best of luck.

Hi,
There is no minimum cutoff marks, but it is good to score maximum marks or rank as it can increase your chances to get admission in best engineering college.

A candidate can attempt JEE Advanced, a maximum of two times in consecutive years. Therefore, candidates who have appeared in JEE Advance 2016 for the first time are also eligible.

Hi,
Yes, you can get admission in IISc without appearing for JEE Mains or Advanced, but you will have to appear for some other all India level exam. Why don’t you want to appear in JEE Mains? You can still apply.
However, IISc is expected to open online application forms for admission in the 2nd week of February, you have to wait till then, for details. But remember that admission is held on the basis of your score in any of the entrance exams you appear for.

It may or may not be possible. If you are getting NIT on the basis of JEE Mains then go for it. If you want to drop then do it at your own risk. If you want to drop then go to Kota else you might get depressed.