The mathematics which the students study now at the undergraduate level is different from what they study for the JEE preparation. There are only a few courses of applied math where you will do the coding, IISER Kolkata offers one such course.
Lastly, if you would like to pursue research in Math then definitely join IISER Kolkata, or if you would like to only do applied mathematics (coding) and obtain a job then you ought not to choose IISER Kolkata.
IACS Kolkata is counted among the top-rated institutes in India. However, if you are talking about undergraduate programs then joining IISER Kolkata will be better. IACS Kolkata just started their 5 year-long integrated BS-MS program. Whereas, IISER Kolkata has offered this course for over 10 years. The quality of teaching and infrastructure is definitely better at IISER Kolkata compared to IACS Kolkata.
Students who get admission for Int-PhD in Physics at institutes like IISc, IISER Pune, or IISER Kolkata score decent marks in IIT-JAM. You should have a rank under 300 if you want admission at IISc. The required cutoff for IISER Pune remains under 500. For IISER Kolkata, you will need a rank under 700.
Here is an interview experience shared by a senior researcher at IISER
Some of my friends attend IISER Kolkata and here are some snippets from their experiences.
This should give you an idea of what it’s like to attend IISER Kolkata.
There are three ways through which you can get admission at IISER Kolkata.
Hope this gives you some idea regarding the admission process at IISER Kolkata.
IISER Kolkata mess facilities offer breakfast, lunch, evening snacks, and dinner to students. For breakfast, there will be options such as boiled egg, bread-butter, cornflakes, idli, omelet, sambar, vada, etc. with tea or coffee. Rice, roti, daal, paneer, fish, chicken, dahi, papad, salad, etc. are available for lunch. You will get samosas, chowmin, bread-butter, omelet, etc. for evening snacks. For dinner, students get options such as rice, roti, daal, veg fry, chili chicken, mutton, dahi, etc.
Here are some pointers on NISER vs IISER.
The Physics department of IISER Kolkata is the best among all the other IISER. It is also the best department among all the departments of the institute, in terms of quality of academics, faculties, research outreach, and management.
However, you should note that just joining IISER Kolkata, does not necessarily mean that you will get Physics as your major. You will need to maintain a decent percentile till your 2nd year to get Physics as your major.
It is difficult to choose when the comparison is question is NISER vs IISER. Choosing one institute over another will not matter much if you stay dedicated to your studies after taking admission. NISER and IISERs offer decent academics and facilities for fundamental sciences. NISER has a great Physics department. If you are choosing an IISER, make sure it is an old one.