Infosys Developer interview questions

Aptitude test followed by logical reasoning test and then interview. Aptitude test was easy as i was preparing for cat. So was logical reasoning. Interview section was average, neither easy nor tough. Questions were focused on assessing the thinking process. I was given couple of puzzles as well. Technical questions were just basic questions, nothing too complicated. How does an AC work? what is engineering? why software when specialization was in completely different field? How does bjt work?