i want to take science with PCM but some of my friends told me that it would be very difficult for me to handle both science and computers.is this true?is it possible to do computer engineering without taking computers in class 11th-12th?and what is the procedure of doing computer engineering?and what do they teach at computer engineering?
It is not so difficult to be honest. You do NOT require to have the computer science subject in your 11th and 12th in order to do computer engineering.
The choice of science vs. commerce is yours alone. However, if you're thinking money I'd say commerce is a better choice. For computer education, it is possible to do BCA and MCA after pursuing commerce in 12th. You can also do B.Sc and M.Sc in Computer Science or IT, but that seems to be unpopular these days in comparison to BCA/MCA
One way or another mathematics is required in computer related fields. Not extensive maths but still it will be there. So, if this is your goal, take something mathematically oriented.
Nothing is difficult if you like it and put appropriate effort. I studied PCMB and never had any problem, and I was pretty good at both maths and bio, mainly because I liked biology a lot. Similarly, if you like computer science, you will do well.
@krishnandu.sarkar: M.Tech is not a job requirement anywhere. B.Tech/MCA + some external certifications is enough. As a recruiting manager from a major software services firm once told me, B.Tech is all that is needed - the remaining knowledge can easily be imparted to candidates via training. Especially in the software field, an M.Tech will net you minimal benefits over a BE/B.Tech/MCA (a slight salary raise at best). It is better that you simply work hard those two years instead, or pursue an MBA.