is analog watch allowed in jee advance centre ? should I carry black pen only or blue ball pen too or don't think to take pencil ?

In order to know what all you can carry to the exam centre of JEE Advanced, I would suggest that you  read the article that is given below. It contains all the do's and don'ts .
http://www.engineering.careers360.com/articles/dos-and-donts-for-jee-advanced-2017

I would also suggest that you thoroughly go through the admit card as it also contains some guidelines as to what to wear in terms of metals and what not to wear.

Be very particular about what to carry or what not to carry in order to avoid last minute anxiety

Do not carry watch with you...
Do not go with pencil and blue pen..
Just black pen is necessary

Dont carry any type of watch....
Analog clock will be there at the exam hall.
Do carry black ball point pen only having transparent body.. (All this is mentioned on the hall ticket. Read it carefully before appearing for the exam.)