It’s easy to tie oneself up in knots about what to expect in the viva. There are simple expectations to hold on to though. Listen to advice and stories from your peers. Appreciate the range of experiences and the common threads that tie them together.
A topic you know really well.
A matter of hours.
An examination with clear goals, and a clear focus for assessment.
Questions leading to discussion.
Two examiners in most cases.
Make it as simple as you can for yourself, and build your confidence and preparation on a few simple expectations.