SCRA

Hi Akash,
For jobs in these sectors you need to clear competitive exams such as UPSC, SSC, SCRA and NDA. These exams can be taken after 12th. For most NDA exams 10+2 in science is required. I will advice you to check the respective websites for eligibility , jobs and notifications.

If you want to become a mechanical Engineer start preparing hard for JEE and then get admitted into one of any IIT's or NIT's. Take mechanical as your branch.
If you want to go for railways. Either start preparing for SCRA or give IES after graduation.
i hope it helps

Hi Manisha,
The Chemistry book(the NCERT book itself too) is decent for entrance exams(except for the organic part, you'll need extra material for that). The math syllabi in NCERT is good in parts, like for integration, but most other chapters are not sufficiently covered hence the extra reference material might not be enough. The physics book is not good at all.
Hope this information helps. Please feel free to revert. Click on the thumbs up or mark it as the best, if you found this useful.
Wish You Luck!