M.Tech

Firstly JEST is to take admission in mostly research oriented Science course if you want to do integrated course of M.Tech Ph.D course, then you can give JEST.
https://www.jest.org.in/eligibility
Here is the eligibility criteria and the institutes you can go for. Also, if you want to do M.Tech then obviously IITs are one of the best option you can check the eligibility and courses offered by IITK https://www.iitk.ac.in/doaa/eligibility-criteria
Also you can check the courses offered by IITB and IITD which have best physics faculty and also ranked in top 200 universities all over the world. I prefer you to prepare for GATE, because all of them take admission in M.Tech from GATE score.

Hello Deepshi, Yes, you are eligible for the NET exam if you are in the final year of the M.Tech. According to your branch in Master's degree, the best option for you is CSIR NET Chemical Sciences. But to apply for the exam you have to score at least 55% aggregate marks in M.Tech. You will also fulfil the age criteria of the exam if you want to appear for JRF I. e. 28 years (maximum age limit). For the assistant professor, you will apply whenever you want, there is no upper age limit. The exam is conducted in three parts I. e. Part A, Part B & Part C. Part A - It is common for all subjects, contains general aptitude questions. Part B - Contains subject based MCQs type questions. Part C - Contains subject based MSQs type questions. Their difficulty level is higher than the questions of Part B.