I'm preparing for PhD a interview. I'm an undergrad and concerned that during the interview I'll be asked detailed questions about what exactly I want to do for my PhD. Is this a normal question asked during these interviews or are they more intersted in finding out about me/my final year project?

They will ask you why do u want to do the PhD, so get prepared, n also please prepare what to say about your final year project as they use this to gauge how u understand research and projects. And also go to Pubmed and do research on any papers they have written and read the most recent and relevant n ask questions frfom that..u will look very interested. Also they will ask u where u see urself in 5 years time!! All the best..u can do this