Yes, you can reappear for the Class 10 CBSE board exams if you fail in a subject.

There are certain rules and regulations set by the Central Board of Secondary Education (CBSE) for students who fail in one or more subjects in Class 10 board exams. The following are the steps you need to follow to reappear for the CBSE Class 10 board exams:

Step 1: Register for CBSE Compartment Exam
- Students who fail in one subject can appear for the compartment exam that is conducted by the CBSE.
- The registration process for the compartment exam is the same as that of the regular board exams.
- Students need to fill the CBSE compartment exam form online that is available on the official website of CBSE.

Step 2: Prepare for the Compartment Exam
- Students who are appearing for compartment exams need to prepare well for the exam.
- It is advisable to consult with teachers and take guidance from them to score well in the compartment exam.
- Students can also take help from online resources such as EduRev to prepare for the exam.

Step 3: Appearing for the Exam
- The CBSE compartment exams are usually conducted in the month of July.
- Students need to appear for the exam at the allotted center and time.
- The exam will be conducted for the subject in which the student has failed.

Step 4: Result Declaration
- The result of the compartment exam is usually declared in the month of August.
- If a student passes the compartment exam, then he/she will be considered to have passed the Class 10 board exam.

In conclusion, if you fail in one subject in the CBSE Class 10 board exams, you can reappear for the compartment exam. The process of registering for the exam, preparing for it, appearing for it, and result declaration is the same as the regular board exams. Make sure to prepare well and take guidance from teachers to score well in the compartment exam.

If you fail one subject, you can make up for it in a compartment test, which is normally held within a few months. You will be declared failed that is if you fail two or more subjects, and you will have to repeat 12th and 10th grade. You have a chance of passing your academic if you pass the improvement test/exam.