I would name the colleges in descending order of preference:

• Indian Association for the Cultivation of Science (they have started the integrated bachelors-masters program recently).
• St. Xavier's College
• Ramkrishna Mission Residential College, Narendrapur
• IISER, Kolkata
• Jadavpur University
• Presidency University

These are the best colleges to study Physics in Kolkata. If you’d consider West Bengal, well then Physics from IIT Kharagpur would be the best.