i want to prepare for rmo ,nsep and nsec plz help me out i am still in class 10^th but will give these exams next yr but want to prepare in advbance

@ amish 
nothing to worry about , rmo exams are easy enough if u are clear with your ncert concepts , frst of all clear your concepts from ncert , focus on imp chapters mopre like carbon and its compounds , gravitation , , ray optics , etc . 
in the olympiads the ques will rotate around these concepts , and remember – not to leave trigonometry . 

there are certain magazines coming like phy spectrum , science trivia etc , take that and they are helpfull . 
u can also find out prev year paper at askiitians 
ALL THE BEST