Hii Imran!
You can refer to the official Website of Bihar Board of Education itself. Most education boards provide the sample papers, model papers and the previous year question papers for the students to refer before exams. You can also access the same through e-library or through our website the link to which is given below-
https://school.careers360.com/download/sample-papers/bihar-board-12th-computer-science-model-paper-2020
Hope this helps.
Good luck!

Hello,

You can get model paper of computer science as well as other subjects for Bihar Board by visiting the following link;

https://school.careers360.com/articles/bihar-board-12th-model-paper/amp

Going through this will make you acquainted with paper pattern,marking schene and other relevant details pertaining to exam preparation.