On the exam day, you should only carry your admit card along with you to the exam centre. If you are appearing in the offline mode you can also take a clip board along with you. However you must ensure that nothing is written on it. As per the guidelines for JEE Main given by CBSE, you will not be allowed to carry a watch. All the exam hall will have a wall clock.

There are many instructions that you have to follow on the JEE Main day. I have a provided a link below where you will get all information to be followed on the exam day. So please make sure that you go through each point beforehand to avoid any sort of hassle.

Hello Kasetty Chandrasekhar. Thanks for contacting Careers360 and we hope we will be able to answer your query. 

Yes, as I had elaborated in a previous question of yours a few hours back, I feel it will be fine to just include the B. Tech roll number issued to you by your college as the qualifying exam hall ticket number. 

Anyways, I would also advise you to contact the required exam authorities either through phone or by email seeking clarification. 

We do not want your career to be spoiled. Hope this helps you and all the best!