There is always a force between you and facebook that keeps you attracting towards yourself but sometimes this force of attraction is covered by the force of scolding of your parents
Theory of relativity: when a student is on Facebook, 1 hour seems like 5 minutes, but when they sit to study, 5 minutes feels like an hour
Law of conservation of brain mass: the knowledge of brain remains the same before the entering of teacher and after his/her leaving the classroom.
For every question in paper there is an equal and opposite answer in our mind unless we know the correct answer
Happiness is always proportional to easy difficulty whereas hard difficulty means a wastage of time and mind both.