We just started magneto statics in school and were told about the use of magnetic monopoles for problem-solving reasons. So we were told that the magnetic length of a bar magnet differs from its geometrical length. I can't quite seem to figure out why we can't assume the monopoles to be right at the ends of the magnet. I do know that a bar magnet can be compared to a long solenoid but we haven't yet studied about either of them in detail and I suffer epic fails whenever I try to get ahead of the class. So a detailed explanation would be really helpful, thank you!