hi,

see in some of the afcat eligibility criteria it is necessary to have 60% score in physics and mathematics individually. if you are not good at physics you would face difficulty at learning during training time. so you must have passed all subjects to become eligible in afcat exam.

airforce group x eligibility criteria is candidates must complete 12th course with maths , physics and english , must secure 50% aggregate score  and 50% marks in English, or candidates must complete diploma in engineering or ITI course after 10th. so if you have compartment in physics you will not eligible for group x exams.

however the eligibility criteria for airforce group Y is, candidates must complete 12th course in any stream from a recognized education board with 50% aggregate score.  so you are eligible for airforce group Y exam.