What will happen if I filed the wrong set number in my 12th board?
I think you must tell your school authority about it and it will be good if they can help you in anyway. Now suppose the teacher who is checking your answers, Pick your mentioned set number and she found that your answers do not match then you can imagine..( this what came to my mind) I hope this never happens but to be on safer side please talk to school people they can tell you real scenario. Be attentive and careful for next exams. Good luck