Hello Gowtham,

Physics, Chemistry and Mathematics are subjects which can be a extremely volatile if not concentrated and worked hard upon. You should choose your weakest subject from the 3 and practice it. When your mind is absolutely fresh. For that you can take a small nap in the afternoon from 3 - 4:45 then freshen up and start studying the subject. You should give atleast 2-2:30 hours a day for a weak subject. Take a break for about 45 minutes. Then take up the subject that is your favorite or which you understand the most and study that for about 1 hour 30 minutes. Take a break for 30 minutes. Then take the last subject and study that for the next 1 hour 30 minutes. This will surely help you as it has helped me to study these subjects.

I hope it helped.

All the best.