JEE

You should have scored nearly 200 and above. So you can get good IITs and NITs. If you are an OBC candidate then your rank will be depended on that year's JEE Mains exam and cut off.

After making the list, it will also become apparent that the syllabus for JEE and board exams is more or less similar. The chapters covered in board exam are theoretical in nature, while those of JEE are concept-based.
1. Confront challenges: Studying the vast syllabus of both the exams can be really

For ethical hacker, you need to take some other specialisation course. It will be a certification course. IIT JEE is required to pursue engineering in different fields.

You should start your preparation. You need to cover NCERT books, and then go through the previous year question paper.

To study organic chemistry, you can opt for SK Malhotra and to learn mathematics, you can opt for the RS Agarwal.

Yes, you should appear for JEE but college stamp is required to fill the form for JEE.

You can collect all the previous year’s questions. You should clear your concepts as well as rigid. You should practice as much as you can. Knowing the theory and formulae, won't help you.
Best of luck.

You need to keep your basic concepts clear. You should study from NCERT books for strengthening the basic concepts. Try as much application based problems as possible. You need to sit for 3 hours and in order to solve these problems. Try and solve all the previous years question papers.

You can refer to the following textbooks:
1. Cengage for mathematics.
2. Dr. OP Tandon for chemistry.