Yeah friend, I am really agreed with u that u have chosen mechanical engineer in your career. U know that becoming an engineer is a dream of every student. I would like to say all the best for your test preparation. As far as your confusion is concerned, I can suggest u in this regard.  u just have to prepare the books of 10+2 level examination with science subjects like Physics, Chemistry and Mathematics. All the basics and fundamentals of these subjects should have prepared by u before appearing for TNPCEE exam.