The interviewer probably won't ask technical questions. For one, the interviewing supervisor might not be in the same art unit as the one that ends up hiring you. And sometimes an art unit's supervisor was in a different art when they were an examiner.
The types of questions you might get are more typical interview questions, like:
-tell me about how you usually formulate a prior art search (for applicants with IP experience)
-what do you think has been the most important (or any important) patent-related, recent court decision
-tell me about a time you applied your technical skills to a problem
-tell me about a time you received criticism on your work and how you handled it
I think they are supposed to keep interviews under thirty minutes, because I've interviewed twice and both ended somewhat abruptly after a half hour.