Not all subject are fascinating We could have an 100 minute period , but our mind should be focused.Right?
For example, i love maths . I used to workout problems 2 -3 hrs solidly without having a break.
But i hate social studies, i used to study the book for maximum of 1/2 hr only and would have break for 10 minutes ,then will continue.
Our perplex mind will be focused on a topic what it likes.
It deteriorates other things which it dislikes.
So having an 100 minute period will be helpful few subjects only not for all .