Government & Defence Entrance Exam

It is never a bad idea to try for NDA. Being a defense person is a matter of great honor and respect. If you seriously want to consider a career in defense, you need to appear for NDA exam conducted by UPSC twice a year. The exam consists mathematics and general ability questions, which will determine your further admission process. To be eligible for NDA, you should have completed your 10+2 from a recognized board of education in any stream. Apart from that, you should be maximum 19 years of age while applying.

RRB Railway Recruitment Board Exam is one of the largest Recruiting organisation in India. The exam is conducted for all education sectors from 10th pass to post graduates.
RRB Exam is mainly conducted in various forms and posts some of them are
Railway Junior Engineer Exam
Railway Section Engineer Exam
Railway group D Exam
Railway Loco Pilot Exam
Railway Non-Technical Posts Exam
Check out more information on https://scoop.eduncle.com/rrb-exams-jobs-latest-notifications.

There is no such specifications to choose the right stream. Any stream can give you chances to write or qualify for an IAS. In general, Arts/Humanities could be the suggested stream to study in and it will help you during your IAS preparations.

If you are not interested in B.Tech then you should go for BA if you want to become an IAS Officer.

Paper 2 of NDA entrance exam is the General Ability Test which carries a maximum of 600 marks.
Break-up of marks:
1) Part A (English)- 200 marks
2) Part B- General Knowledge- 400 marks
a) Physics Section- 100 marks
b) Chemistry section-60 marks
c) General Science-40 marks
d) Social studies-80 marks
e) Geography-80 marks
f) Current events-40 marks

You can become a police constable just after 10th. You have to write the exam and you must be physically fit. Go ahead.