An interview is a two way street. It’s not just “sit there and answer questions”. A good interview goes on like a regular conversation. Your potential employer wants to get to know you. Be prepared to answer their questions of course. But a good interviewee will also ask questions at some point during the interview. Ask what are goals of the department and ask what type of responsibilities would be required of you. Find out whether this is the right job for you.
Asking questions will show them that you are also job shopping and have other options as well. It also shows that you want to see if you’re interested in the well being of the company, which is always a plus.