How long is too short? Each exam in my BSc Applied Physics final (1977, Exeter Uni.) was three hours and we had similar exams in each of the preceding years to weed out those who weren't keeping up. I'm pretty sure that having more time would not have helped the weaker students get through the Quantum Mechanics exam.

In addition I had to defend the report (120 pages of typescript and charts) of my final year project to my supervisor and another senior academic. And it was clear that they had actually read it.

All those exams were open note; anything in your own hand or a copy of a lecture handout was permitted. Again the weaker students would not have been helped by more time because they hadn't understood that you have to have enough familiarity with your notes to be able find the right information. Some brought in 50 litre rucksacks stuffed with ring binders and the noise of them furiously leafing through was enough for the invigilators to warn them to make less noise or risk being ejected.

In Norway it is typical that an exam of similar standard allows five hours.

3 hours for us as well. When you start doing graduate level work, a problem could easily last over an hour. And many people will have false starts before they figure it out.

It's not a problem with homework assignments as they have multiple days to finish.

So the professor has to decide between poor data with high variance, or good data with lower variance.

> I'm pretty sure that having more time would not have helped the weaker students get through the Quantum Mechanics exam.

Funny you mention that. When I did my (undergrad) QM II exam, I likely got the highest score, and I'm sure my score was below 40%.

There just wasn't enough time.

I sat one exam at uni (in person, invigilated) for History and Philosophy of Science, which had no time-limit. You could take as long as you needed, whether that was one hour, five hours or all day.

Pretty much everyone still took three hours. But you felt so much calmer, knowing you weren't racing against the clock.

All of my exams were three hours as well. I don’t think there’s a single instance where more time would have helped me. If I didn’t immediately know the answer to a question, I’d just move on, then revisit. When you don’t know the material/answer, more time won’t help. But you do have to know how to take a test and manage your time.