What is the difference between BSc and BTech specifically in computer science?

B.Tech or B.E deals with technical aspects whereas B.SC is a course of Basic Science.
First I must focus the difference between B.Tech and B.SC. B.Tech is all about the present and future requirements of the industry. B.Tech will teach you to invent new software, explore new things beyond imagination. B.SC would focus more on existing softwares and their present use, but limiting the possibilities of inventing or discovering new softwares. You are given various projects (practical ones which require minute to minute details) in B.Tech whereas you will be given theoretical assignments in B.SC. The simplest difference I can tell you between both of them is that B.SC will focus more on derivations of a topic, whereas B.Tech will focus more on applications of a topic. B.SC is more theoretical as compared to B.E.
Now coming to the point of opportunities, India has presently more opportunities in B.Tech as compared to B.SC
Companies are facing an acute shortage of good engineers. Engineers have a better pay scale than B.SC graduates. There are more colleges for B.Tech CSE as compared to B.SC CS.

Let me now focus on the advantages of B.SC CS.
BSC CS would offer good research opportunities. If you want to become a teacher, BSC is a good option.It is of 3 years as compared to 4 years B.Tech. It has much fewer fees as compared to B.Tech Course.

Now, I would like to give a bit of personal advice to you. Never ever drop a year to go to IIT. There are very few( or rare) students, who go to IIT after dropping. You might get a good rank next year but the risks are too high because most of the students are not able to score a good rank after dropping because of peer pressure. Also, it is difficult to study all those subjects which you have studied in the last two years. It is really exausting to study all that science stuff and give all those tests again even if you are passionate about science. If you are getting admission in B.Tech CSE in a good government college( It might not be an IIT), go for it. Otherwise, go to DU. DU is really good.
Think carefully before choosing your career as your life depends on it.
Good Luck!

B.Sc is a three year degree course and the maximum papers to be chosen are three and the combination would varry as per requirement. It might be a combination of Physics, Chemistry and Mathematics or alternatively Physics, Mathematics and CS and so on.
While studying in B.Sc, you will be gaining detailed theoretical knowledge in the subjects being persued apart from the practical papers where you would not have enough exposure in the practical area. So in case of perusal of computer - science in the B.Sc stage, it would not be enough for you and you need to compensate it by taking up an MCA course from a reputed institution.
But the case would be somewhat different, if you opt for B.Tech from a reputed Engineering college with the stream of computer science. It would be a four year degree course enabling to explore the different domains in the computer - technology with the detailed exposure in Java, C++, Oracle etc.
With a good faculty, your confusion in the subject will be wiped out making you a competent engineer who can explore the techniques in the hours of crisis.
However, if you are interested for IIT, make an attempt to clear the same at the first attempt.Even if you could not clear IIT advanced and in the IIT mains you secure around 180/ 360 marks wherein each paper Physics, Chemistry and Mathematics carries 120 marks, you will be placed around 95 percentile making you eligible to choose Computer- science in NIT's consisting of 31 in number. These institutes being the government aided institutions having nominal admissional charges but these institutions are as good as IITs.
The other institutions such as Thapar Institution of Technology, Patiala, Vellore Institute of Technology vellore.BIT Pillani are equally good.
In an exercise to get admission in IIT, don't loose a year and you will have many options such as SGIT Indore, Madhav Rao Institute of Technology - Gwaliar. Hence make a prudent choice while considering admission in an Engineering college offering you a grand career in the field of Computer - technology.

B.Sc is a degree in Science which deals with mainly the theoretical part of the subject. You may be doing some practicals also in this degree but the main focus is on the theory and much exposure will not be there for the applications part of the subject you have studied. It is a three years course. The admission to the course will be based on your marks obtained in your +2 or Intermediate. There are a number of colleges for B.Sc course. These days many IT industries are employing B.Sc Computer Science candidates by paying lesser salary.
B.Tech/BE is a degree in technology or engineering. These subjects deal more with the application part of the science. Here the focus will be more on the application of your knowledge for various requirements. It will have more project works, pieces of training and advanced uses of the scientific investigations in various fields. It is a four years course and they are a good number of colleges for these courses. But generally, the admission will be based on the rank you have obtained in the entrance test.
I advise you to go for B.Tech or B.E. In case you are not able to get a seat in that then you can think of B.Sc.

Also, I would suggest that you can go for BCA or BCS. They both are good computer courses providing ample opportunities.

B.Sc. in computer science and B.Tech. in computer science are more and less similar as far as the basic syllabus is considered but in B.Tech. more coverage is given from engineering aspects of this stream. Now depending upon your interest you can go for any of them and if you score good in B.Sc. then you will have opportunity to do some advanced courses in this area and then try for a job or start on your own. There are many courses like Animation, Web Designing, System Management, Data Base Applications, Financial Softwares, Digital Marketing, Networking etc which can be undertaken to enhance the knowledge in this field and then go for the related jobs. Alternatively, after B.Sc. one can head for the integrated PhD course in the select institutions or go for M.Sc. or M.Tech. in this line and qualify NET and then apply for lecturer post in the universities.

If you prefer B.Tech. mode then you will have to score very good in order to get placement through campus recruitment and if you do not get success in that then you might have to apply in Govt and PSU jobs where the B.Tech. in computer science stream students are taken after a written test. For meritorious candidates there are scopes in the IT industry.

In any case whether you do B.Sc. or B.Tech., being a graduate, you are eligible to appear in the Central or State Administrative Service, Railway Services, Defence Services, Teaching areas especially private coaching centres, Banking Services etc. If computer is your core area and you want to work in it only then going for diploma in advanced computer skills like effective coding, SAP, software platform development for new businesses, financial and commercial software development, softwares for R & D in science and technology and other similar ones makes sense before applying for a relevant job.

In my opinion whatever mode you select whether B.Sc. or B.Tech., you must concentrate and focus for achieving the top most score and then top up your skills and knowledge with additional certificate or diploma courses.