It's okay to ask these basic questions. It's never directly addressed because people just assume you know, but if no one ever told you, how would you know?
It really depends on the rotation. For example, for surgery, generally speaking we arrived at 5am for pre-rounds and stayed until 5pm-7pm on regular days. On long call days (every 4th day for one month), we stayed until 9-10pm or so but had no post-call day and were back at 5am the next morning. On overnight call days (every 4th day for one month), you get in at 5am and stay until about 11am the next day. Then you have the rest of the day off as a post-call day. I was very lucky in that I generally got off Saturday afternoon and all day Sunday every week which was pretty generous.
For family practice, it was 7:45am until 4-5pm Monday through Friday with no call.
For internal medicine, we arrive just before 7am and leave around 5-7pm on regular days and around 10-11pm on long call days (every 4th day). There is no real post-call day, but teams generally round 1/2 an hour to an hour later after a long call day. You get one day a week off which can be any day but should not be long call days.
Pediatrics is fairly similar to internal medicine, ob/gyn is similar to surgery, and neuro is similar to family practice. Psych is generally easier hours, coming in around 8:30am and leaving around 4:30-5pm but we take long call once a week at the psych ER meaning you stay until around 11pm or so. Weekends are generally off but not always.