as I am ISC 12 student if I will practice cbse 12 previous years paper that will help or questions my repeat in ISC 12 boards
Hello Abhishek,
ISC and CBSE are two boards that follow very different question and marking patterns. For example, the CBSE paper of Maths will be quite tougher as compared to ISC maths paper but the English paper for ISC will be tougher as compared to English paper of the CBSE Board. If you want to practice just for the sake of practicing then I suggest you to go ahead as the more you practice the papers the more you gain knowledge for your exam but if want to be dependent on just the previous years' paper for your current exam, I suggest you to not take such a big risk.
What you can do instead is solve last 10 years' ISC papers because it will give you a better and fair idea of what kind of questions you can expect. Most of the times, the questions of previous years are repeated.
Hope you found this answer helpful.
Best of luck for your ISC! Study hard!