Lateral entry

For lateral admission, if you are from the Tamil Nadu, you better go for SSN- Chennai. If your family is good enough to spend more money, go for Amirtha, VIT, and SRM, if you are willing to go for other state, choose Gujarat based college. Most of the reliance recruitment are from Gujarat based coll

You don't need to go to any specific book for the exam. Just brush up your Diploma concepts. The exam consists of basic mathematics, physics, chemistry and English questions. You'll find a list of topics that they ask from on the admissions page in the manipal.edu website.

B.Tech lateral entry course is provided by NIMS University, but not necessarily for petroleum engineering, you need to check with the college for the same.
https://www.shiksha.com/b-tech/course/b-tech-lateral-entry-nims-university-nims-jaipur-236275

Dear Manjeet,
Below mentioned is the URL. Kindly go through it. IIPM provides a direct entry into 3rd semester.
http://www.iipm.co.in/MBA-Lateral-Entry.htm
For further details, you can directly get in touch with them.

You can't apply in Army Institute of Technology with Diploma. But, if you appear in JEE Mains and score good enough (assuming you as army personnel ward) that ranks under 1 lakh you may get in. All the best.

For the entrance exam, you need to have knowledge of basic and applied grammar, besides some competence for simple translation from the language concerned into English and vice-versa.

If you are having a 3 years Diploma, then you can take admission through lateral entry program directly into 2nd year for B.Tech.

Yes, the option is available to you.
Read the Eligibility details below:
M.Sc Computer Science (SW) PART-II (Lateral Entry Scheme)
Pass in any one of the following examinations of this University or any other University/ Institute/DOEACC Society recognized by UGC/AICTE/DEC/Govt. of India/State Governme

Kurukshetra University does not seem to facilitate such a thing. The 2 Years MBA prog takes admission in First Year through established procedures.
http://www.kuk.ac.in/information.php?action=showContent&abc=L3&L01_id=OA==&L01_direction=H&L03_id=ODM=&L02_id=NDQ=&sublevel=y
The Department of Management