Exam

Hello Karpagalakshmi Padmarajan, this college for women had reported cutoffs around 60 in previous years. Considering this, i am sure that you will get admission since you have a score of 73. If course cutoff varies for different categories of students. To help you I am attaching a link that will give you all the required information.
https://www.shiksha.com/college/psgr-krishnammal-college-for-women-coimbatore-22882/cutoff
Best wishes to you.

Yes, you can give an exam but one must have studied the subject for 3 years in which he/she wants to give an exam. For greater details about eligibility for a particular subject, go to the IIT JAM official website. From there download the admission brochure, and you will get to know more details regarding eligibility.

Yes, you can try and attempt entrance test separately for IIIT Hyderabad. They provide separate entrance for students. IIIT Hyderabad is offering direct admission in B.Tech ECE & B.Tech CSE courses without the requirement of JEE Main percentile or score. The admission is offered through IIIT Hyderabad's Special Channel of Admission (SPEC). So Yes, it is possible to get admission in IIIT without JEE Mains.

Many IITs demand that a candidate should have a minimum 10+2+3 qualification for getting admission through the IIT JAM exam. But still one can contact the IIT JAM organizing institute. Go onto the official IIT JAM organizing institute website then you will find their contact number and e-mail IDs then contact them.

Pantnagar university is offering many programs in many streams. It's a agriculture University
For entrance in Science, it will need the 11th 12th Physics Chemistry and Biology and agriculture for those who are having agriculture. Exam level is near to the NEET and from basics to deep many things are asked. I can answer better if you can tell me for which course you want to enroll in Pantnagar university.