B.Sc

Hello Shroshtabh,
These days many states are turning into ghettos. Not allowing students from other states! However, fortunately, this is presently limited to courses for which there is a huge rush of students. For B Sc, there is no issue and you can seek admission in CU.

Yes, it is a pretty good college.

It depends on you. The minimum salary would be 10-12k, if you crack MT programme then you will get 25k or more than that. It also depends on your department for which you are interest.

Hello Suvam,
As far as further studies are concerned, I think you have to appear for GATE or some other exam after B.Sc to get admission in M.Sc. IITs were established to provide finest technical manpower for building the nation. IISc was established by private bodies to conduct core research with a focus on advancing the scientific capabilities of the country.
You see hell lot of IITians in companies running here and there with a shiny life style and if you get a chance to go to IISc you feel the calm and focus without much shiny life style and a commitment to research and scientific advancements.
Hope this helps! All the best!

Apart from 60% minimum in maths and overall in 12th, the basis of selection followed by DU is as follows.
Selection will be made on the basis of best four academic subjects including one language, mathematics and two subjects out of Physics, Chemistry and Computer Science / Informatics Practices. The students of other streams: one Language, Mathematics with two Academic Subjects (LIST A) with a deduction of 2%.
What you are asking might be followed by some private or other state universities for that you have to check them individually.

Hello Arijit, to decide the better of the two, compare their placement ratio, average package and main - which one are you really intrested in:
https://www.shiksha.com/it-software/course/master-of-computer-application-sikkim-manipal-institute-of-technology-sikkim-manipal-university-gangtok-249787
http://www.ignou.ac.in/ignou/aboutignou/school/sos/programmes/detail/165/2
Hope this helps! All the best!

Greetings.
Kindly inquire about the same on www.cuchd.in. members concerned will revert you back as soon as possible.
With respect to your course, valuable feedback will be provided by the University in an efficient manner.