Job after B.tech

Your salary will be decided by several factors and the question can't be answered directly. However for a fresh graduate, the salary, as far as I know, is a function of which company you join. I believe the gap between the salaries offered by IT & other industry is bridging. I'm strictly against choosing career based on salary expectations. It may look like a sane option at start, but in the long run, you'll end up being average or below-average.

If your interest lies in Electronics - go for a job in a company that offers it. If software is your interest - go for IT job. But don't let the salary decide it. First step is crucial one and you can't afford to go wrong at it. You can command any salary provided you are 'indispensable' to the company. But for that you've to work in the field of your choice and interest.