Science

Yes, JAM is an entrance exam specifically for M.Sc Courses IIT's. It is mandatory only if you want to pursue an M.Sc at one of the IIT's. Other colleges have their own eligibility criteria. IIT JAM Eligibility Criteria mandates: candidates to hold a Bachelor's Degree. Candidates belonging to General/OBC (Non-Creamy Layer) category must have at least 55% aggregate in Bachelor's. The marks secured include all the subjects studied at the graduation level, without rounding off the marks. IIT JAM is one of the toughest exams conducted in India. So, prepare yourself well for the exam. IIT JAM 2020 Exam will be conducted in the month of February 2020. So, you have enough time left for the preparation. Start your preparation now. This will give you enough time for the revision. Maintain a timetable so that you are able to prepare for the exam in a planned way and give sufficient time to the subjects that need more attention. Refer best books and study materials. Better If you can take up Coaching. Solve previous year question paper and take online mock tests regularly. It is possible that you are very strong in one subject and weak in the other. Do not get discouraged by the same. Try and work hard more on the weaker areas to strengthen them.

Hi,
It all depends on your interest and ambition. You can do M.Sc and Further Ph.D. Graduates in pure Science have multiple options. Some of them are as follows:
After the completion of the course one can go for higher studies M.Sc. Or PhD
Since pure Science is gaining popularity educational institutions are offering placements in their institutions/universities
If you have inclination for research you can pursue research in the related field. There is huge demand for pure Science students in the west in the research arena
Pure Science opens up plenty of opportunities in the fields of state and central research organization. They can also work for public sector undertaking, which has huge demand in the recent years. So I would suggest you first analyses what you want to do, accordingly choose the Patch. My Personal Suggestion - you should do M.Sc for better Job Prospects.