Electronics and Communication Engineering

Hello,
After completion of Diploma in EC, you should opt for lateral entry admission in the second year of Engineering. You can opt for Electrical and Electronics Engineering, Electronics, Electronics and Telecommunications branch of engineering as per your own interest.
I hope this answers your question to your satisfaction. If you have any further questions, kindly revert.

It depends on your priority like package, company, etc. Both the colleges have good brand value.

You must specify your category and the exam you took for an accurate answer, but assuming your category to be general and the exam to be JEE Mains, you might get some good pursue.

You have no option other than paying entire fee of 4 years to your current college. You must get a seat in the other college.

It is very difficult to compare these two colleges. I think fee may be deciding factor. BIT Mesra has slightly high fee than pursue Rourkela. Campus of pursue Rourkela is larger than BIT Mesra. Placement wise BIT will win the battle. But these days BIT is facing placement problems but you will be placed for sure. Coming to brand name, I will rate both the colleges equally. Another factor may be distance from your home city.

The fee is approximately Rs. 1.50 to 2.00 Lacs for every branches in Institute Of Technology, Nirma University. Thus, the fee for EC Branch will be same as above.

With this category rank, you can try for some low rank NITs. I guess the rank must be enough to get a seat in some of those. Else you can also try for some regional engineering colleges for the same.
Good luck!