You are expected to ask questions at job interviews. It's the law. To neglect asking questions is one of the cardinal sins of job interviews - I'd place it somewhere between turning up late and sneezing into your hand then wiping it on the chair. Not asking questions can count against you, resulting in a failed interview, or even, in some cases, death by impalement*.
A good question shows you're interested in the job and the company. It also uses up time that your interviewer might otherwise spend asking you difficult questions about your lack of semiconductor knowledge or your unsuccessful attempt to join the Foreign Legion in 1998. Asking questions gives you time to sit back and listen to someone else talk while you eat your digestive biscuit. Simply, questions WORK.
The question is: what counts as a good question?
A good question is one that a) shows you've done your research or b) shows you've been listening.
Conversely, a question is bad if it reveals that you haven't done your research, or if it shows you haven't been listening.
In other words, don't ask questions about stuff you should have googled prior to turning up at the interview. Ask questions that require the interviewer to go deeper into things you've already researched, or into things s/he has already said.
Good: 'I noticed that your product has over one million conical nozzles. What kind of machining techniques do you use to make these?'
Bad: 'So, what do you make around here, anyway? Is it... light bulbs? No - wait - cat flaps?'
Next: more about questions.
* rare, admittedly