I was recently asked how many questions a candidate might get in the viva. What is the range like? wondered the nervous PhD. Was there a minimum or maximum number?
I tried to apply some logic to come up with some numbers, but gave up – the question is a red herring. Examiners will have a lot of questions in mind, some driven by your field, some by their interests, some by your thesis. They’ll have questions that you can expect, and some that you can’t. They’ll ask questions that they didn’t know to ask until you said something interesting in the viva too.
I don’t know how many questions will come up in advance of your viva: we could only know that after the fact.
If you’ve read this blog before then you’ll know I have ideas about how you can prepare for questions though. Do a good piece of research, write a good thesis and spend some practising answering unexpected questions to build your confidence.