Science

Firstly, you must score a good percentage in your B.Tech CS branch. Especially above 8 CGPA. You must have talent along good academic score. It totally depend upon yourself that how you perform in your job interview, written test and the group discussion round. Have you completed your B.Tech? Or you are pursuing it. The scope is very good in job perspective for a CS engineer. Just focus and have skill, talent in your self. And mainly the confidence you must keep at every situation. Just believe in yourself. Similarly the chances you have for jobs in foreign country too. For any further query please feel free to ask.
Best of luck.

Certainly not. You need to check the entire syllabus of your stream related to GATE. Aptitude is a small portion of GATE Syllabus which consist of 7 to 15 marks in the exam. In order to get good rank you need to cover the syllabus and practice ample amount of problems. Completing only few topics won't help you in clearing the cut-off of PSUs and IITs.

Joint Entrance Examination (JEE) Mains. Purpose: For admission in BE/JEE Advanced. BITSAT. VIT University Engineering Entrance Exam (VITEEE). National Eligibility Cum Entrance Test (NEET). Indian Maritime University Common Entrance Test. Indian Navy B.Tech Entry Scheme. Indian Navy Sailors Recruitment.

Hi Shreya,
If you have passed your 12th board then you can get admission in IIT or NIT for Integrated M.Sc or if you have cleared your B.Sc then you can go for JAM for only M.Sc in IIT. You can also choose some state government colleges.
I hope it will help you.

Educational Institutes
Space Research Institutes
Hospitals
Health Care Providers
Pharmaceuticals and Biotechnology Industry
Chemical Industry
Environmental Management and Conservation
Forensic Crime Research Firms
Testing Laboratories
Geological Survey Departments
Wastewater Plants
Aquariums
Forest Services
Oil Industry.

A. R. C. Viswanathan College, Bharathidasan University-Tamil Nadu.
V. M. Sri Pushpam College, Bharathidasan University-Tamil Nadu.
Atma Ram Sanatan Dharma College, University of Delhi-Delhi
Auxilium College, Thiruvalluvar University-Tamil Nadu
Banshi College of Education, Chhatrapati Shahu Ji Maharaj University-Uttar Pradesh
Beni Madhava Singh Mahavidyalaya, Chhatrapati Shahu Ji Maharaj University, Uttar Pradesh.

Yes, science stream is mandatory to pursue B.Sc.

Yes, regular classes are mandatory for B.Sc (Hons).