A typical day would start with a stand-up meeting where I would relay the status of my work to the team. I then worked on my tasks, which varied but would include writing unit tests for the source code, implementing code changes, prototyping code, updating and writing documents. Throughout the day I would often need to talk and work with my colleagues for advice, help or information I needed for my tasks.
I would strongly encourage someone to do a placement year, not only does it give you an opportunity to develop your skills and apply them in real-life projects, but also gives you a valuable insight into your career path after university.