Hi Aspirant,

I understand that you are facing a dilemma for pursuing BSc. Physical Science with Computer Science from Delhi University and so to answer your question, the difficulty level for a particular field of study is entirely dependent on the level to which a student has prepared himself or herself for the examinations. If a student studies diligently and has put in significant effort in the preparation for the same then he/ she might not find the examination difficult whereas if a student has not prepared well will most definitely find the examination to be difficult.

Now coming to the second part of your question, this aspect of preparation is entirely dependent on the student as every student is unique and thus has an unique level of learning capacity. For better understanding, X student might take 3 hours to learn a chapter while a student Y might do that in a hour. So that's up to you as to how you will plan your strategy to get the best grades.

BEST WISHES!