JEST

Hi!
You can find the eligibility information here https://www.shiksha.com/science/jest-exam.

Admit card details can be found in the link below:
https://www.shiksha.com/science/jest-exam-admit-card
You can also contact the helpline number or check the FAQ from the link below.
https://www.jest.org.in/frequently-asked-questions

Kindly go through the eligibility from the link below. https://www.shiksha.com/science/jest-exam.

Hello,
To appear in JAM Exam, you only need a graduation degree with minimum 55% marks for General & OBC and 50% marks for SC, ST categories. You also need to satisfy all the other eligibility criteria for the exam. Click here http://bit.ly/2HxUej2 to know the complete eligibility criteria of IIT JAM Exam.
Best of Luck!

Yes, you can apply for the entrance. All you need is that you have 50% aggregate or more in your B.Sc physics. University you do from doesn't matter much.

You need to have done your B.Sc physics with 50% aggregate to apply for the entrance exam.

Most of the institutes do call for an interview after you qualify the JEST exam and you've to apply for them based on your rank/marks. So, just see the pattern by which institutes called for interviews in last few years.

JEST is Joint Entrance Screening Test. It is a screening test conducted for the candidates who want to pursue M.Sc. Integrated Ph.D and Ph.D programmes. Joint Entrance Screening Test 2018 will be conducted in the second week of February. JEST Exam is conducted for the following subjects:
Physics
Theoretical Computer Science/ neuroscience/ Computational Biology
A candidate can appear in either Physics or Theoretical Computer Science subject, but not both.

Firstly, JEST is an entrance exam, so let me reframe your question, it should be - "What is the minimum percentage required to give JEST and GS (entrance exam conducted by TIFR) exams?”
Answer:
60% minimum percentage for you to be eligible to give the exam which is actually followed by an interview so definitely it is not an easy thing to get TIFR or Some university through JEST for integrated course as they demand for actual creamy and determined researchers in their institutes, And they don't take any admission on merit basis so it's better to start preparing for entrance exams.