All the students who have taken the class 10 and 12 CBSE board exams who wish to apply for re-evaluation of their answer sheets will have to pay Rs 500 per subject. As soon as the results are declared the link for same will be activated on the official website – www.cbse.nic.in You will have to pay Rs 700 and Rs 550 per subject for class 12 and 10 respectively if you wish to obtain a photocopy of the answer booklet.
Source: https://indianexpress.com/article/education/cbse-results-how-to-apply-for-reevaluation-know-entire-process-cbse-nic-in-5671835/
