Hello Suresh,
It is not mandatory to reach the exam center by 7.30 a.m, but it is advisable to reach the examination centre ON TIME just to avoid all the unfavourable reasons of being late or not finding the examination centre. You will not be allowed to enter the exam hall if you are late to the centre for both papers. Reaching early would also help you to complete all the frisking process early and concentrate mainly on the exams ahead of you. After you entre the examination centre your biometric registration/ verification would be done for the exam. So you should be in the exam hall at 7.45 for paper 1 and 12.45 for paper 2. ALL THE BEST !!

Yes, you should reach the centre by 7:30-7:45 A.M on the examination day. Getting late can let you in a lot of trouble, so be on time. Reaching early is not a problem, but reaching late can lead you to many problems.