This is really shocking!!
A study in electronics should provide you with knowledge about transistors and OPamps, as these are the basic components of each discrete analog circuit. Even in digital circuits you can find them often. So, there's absolutely no excuse for these unqualified idiots!

By the way, I woud ask those candidates differently, to find out, whether they have experience in electronics or not. I would ask: "Have you already seen a switcher circuit? What components do you need for it? Is a transformer a good thing with it? How to stabilize the output voltage at secondary winding of such a transformer? How is isolation provided then?"

Important, I wouldn't want to hear very concrete answers, because if you have had lots to do with many many circuits, you cannot have every detail in mind, that's impossible. But I would want to hear, whether he had ever worked with such a thing in the past.
In electronics broad band knowledge and experience is more important than to be a master in a very narrow section. So, I would look for this braod range orientation, when having a candidate.

Kai