There is no exact cutoff for B.Sc Physics. Loyola cutoff varies each year, based on competition. The required cutoff also depends on other factors such as caste and religion.
Overall, if you have an aggregate of around 80% in Physics, Chemistry, and Mathematics, there’s a good chance that you will get a shortlist.
One of my friends graduated from Loyola College and here’s what I got to know from her. There is no fixed benchmark standard for admissions at Loyola College.
If you have an aggregate of over 80% in Physics, Maths, and Chemistry then there is a pretty good chance for admission into Physics, but again totally depends on competition.