You should always choose the branch according to your interest, passion and your skills.

The most important thing is to choose the good college. If you take admission in top college of engineering all the branches will provide good placements.  

Before choosing any branch you should decide which type of

Yes, there are numerous exams for the diploma student in mechanical department depending on the line you wanna pursue. You can opt for the recruitment exams. 
In the recruitment exam, there are so many exams conducted to join the PSUs, state and central government organizations, educational institutions, banks etc.

See this will entirely depend upon the college and university you are studying under. Try and check with your professors about this and see in the library too. 

Bhilai institute of technology Durg chattisgarh is the best option In the comparision of Government Engineering College of Raipu. For its genuine reviews you can go through with given below link.

Bhilai institute of technology Durg chattisgarh

Government college of Engineering

the opening and closing rank for home state category students from sc would be around 350-1560 

and for the other state students of sc category, the opening and closing rank must be around 660-1880

and coming to the scoring of marks one must score 200+ to have a sound sleep

You can check the top NITs for Mechanical Engineering below

National Institute of Technology, Tiruchirappalli

National Institute of Technology, Warangal

National Institute of Technology Karnataka, Surathkal

Motilal Nehru National Institute of Technology, Allahabad

National Institute of Technology, Rourkela

To check the closing rank of all the NITs you can refer

Dear Ash Singh,

According, to previous year you need to score around 210 marks in JEE Main to get Mechanical branch in DTU in general category outside Delhi region.

Good Luck!!

According, to 2017 allotment you need to score around 160 marks in JEE Main to get mechanical branch in NIT Jalandhar in OBC category other state quota.

Good Luck!!