I'm an engineering student(mechanical ), i find it hard to revise at night(at 10.00 pm or above ).what should i take to stop feeling sleepy and tired.

May need more sleep: Multiple studies have shown that our maximal and most effective learning is limited in a the day. The best way to get energy is to make sure you are geting adequate sleep, some would argue 7.5 -8h per night, others will say at least 6h, but this is also depenent per person. However, eating healthy, staying hydrated and regular exercise all help. If all else fails, take a powernap.