Obviously every boss may demand from us the knowledge about other field of expertise. In all honesty, it's not as stunning as it may seem. That's the reason we all should really know what the expectations of the future employer are and whether we are capable of fulfilling them.
However before we start, why these questions will help? Well, first of all, you will learn how to answer some complicated questions prepared by the employer. Even if you feel pretty self-confident and you understand that you have got enough knowledge to be a great worker, your frame of mind towards the work or even the way you act may be adequate reason behind the interviewer to send you off.