Actually, there are stupid questions...those that are deliberately stupid. I used to make those up for my instructor when he wrote in my student record that I never asked enough questions--that was supposed to be an indication that I knew what was going on. So I asked him questions about electronics, usually keyed off of something that I'd read ahead about while he was speaking (which I always did, because he was boring boring boring when he'd practically read verbatim what he'd asked us to read the night before--I guess he was correct that I wasn't paying attention.) I'd deliver the lovely when it was appropriate.
Such as, when talking about the duplexer section of the radar (the part that switches the antenna path between the transmit section and the receive section), I asked what the T/R tube (that basically grounds out any transmit signal to keep it out of the receiver section) looked like inside. It's also called a "spark gap", which pretty much means that there are two contacts for the signal to "spark" across when it reaches a certain level.
My favorite question, though, was about transistors. Transistors have two types of conductive material, doped to be either positive (P material) or negative (N material). Common transistors have three sectors, and are designated by their composition: PNP, or NPN. My question, of course, was another "What does it look like" sort of question: "Can you tell the difference between P and N material just by looking?" Later instructors were intrigued enough by the question to cut the can open, but not this fellow.
I was such a bad student. We could read the dread in his face when my hand went up. I smiled so sweetly during the next assessment when I asked if I was asking enough questions....
As an instructor, later, I had those sorts of questions. The let's-see-if-we-can-stump-the-instructor questions. Usually, they dealt with a circuit that we were covering in brief, or the inside of integrated circuit chips where we just looked at the outputs. In the first case, it was the first time teaching that course myself, and I think it might have been the second time teaching that lesson. The student asked; the rest of the class gave him "The Look", but I ploughed through the conduction paths and to everyone's surprise, including mine, it made perfect sense when I was done.
The second time, I pointed to the releveant section of the tech manual and invited him to come in early and discuss the circuit if he still had questions. Oddly enough, he didn't.
There was a point to all of this, but my morning caffiene hasn't perked through my system yet.