If you're doing something along the lines of historical studies, below are some questions I've gotten from interviews:
1. What got you into wanting to study this field?
2. What type of history are you thinking of writing/how are you approaching the question (cultural history, social history, intellectual history, institutional history, biographical, etc...)
3. Are you familiar with X work? (since they're experts in the field, they may ask if you're familiar with someone else's work)
4. How is your work different or engaging with X's work (building off of the previous question, but still working on your familiarity with the current scholarship)
5. What's your long-term goal? What schools are you hoping to find employment in after you graduate from this program? (This question is about knowing what type of schools the department targets and the focus of the program compared to others, like seminaries vs. liberal Christian schools vs. state schools)