From class I to X, there is no off period(s) from there starting to end in any G.O. Say for an example, V is finished in 5th period, then VI is finished in 6th period. VII to X are finished in 8th period. All the students get recess at tiffin period. You may take the recess of the tiffin period as a gap. A few school terminate there classes after 2nd period shortly for 10 minutes, and they allotted for the tiffin for 30 minutes. It is recommended by the MC. Continue classes are normal. In case of XI & XII, there may be fallen gap period according to there infrastructure of class-room, laboratory, subjects, teachers etc.