The contact hours for physics will be high regardless of your year of study. I found that I was often on campus for lectures by 10 am ish and would leave by 4 or 5 pm on average. Of course, that would vary, sometimes you will have a 9 am lecture, other times you won't have anything on until the afternoon but could have a lecture finishing at 6 pm so it really depended on the day but on the whole I was on campus every weekday for a good chunk of the day. I found that this worked quite well for me personally though as I found it much easier to do work on campus compared to at home, there are fewer distractions. I loved the atrium in the department. It is a large open space on the ground floor of the department that has many large group tables. My friends and I would often sit there and work or have some lunch in between lectures, it was just a really nice environment.
With this in mind, I wouldn't really recommend commuting unless you live relatively close to Lancaster. As @Ghostlady
has already helpfully pointed out the on-campus accommodation was slightly cheaper than at other universities I was considering back in 2018 (wow that makes me feel old haha!). Standard accommodation, which is one of the cheaper options on campus as you share bathrooms, is currently £116.90 per week on a 40-week contract. Most people will stay in on-campus accommodation in their first year and then usually move out for the second year and beyond. Off-campus accommodation tends to be a cheaper option with prices averaging around £95-105 per week, in my personal experience. Of course, on campus you have the convenience of being close to lectures and labs so living off campus you will also usually want to buy a student bus pass which appears to be on sale for £305 for the three terms of the next academic year.
For a bit more of a detailed breakdown of contact hours read on haha. In first year you'll have 3 modules on at once. These modules are 5 weeks long and there are 5 blocks of them across the year. You'll have lectures and workshops for these, usually 8-12 hours per week in first year, along with 3 hours of seminars and a 3-hour lab session (these were one afternoon a week in my experience). In later years the amount of lectures is roughly the same although you may only have two modules at once, it can vary depending on your stream (ie particle, astro etc.) and the optional modules you choose. I did general physics and in my second year, the lab sessions extended to a day in length rather than just an afternoon. In third year I had some optional modules and chose to do semiconductors and low temperature labs along with a particle physics group project that was based in the radiation lab. Finally, the fourth year is the MPhys year so I did 6 lecture modules and an extended research project. My project was lab based so I was in the labs a couple of days a week, basically anytime that I wasn't doing my worksheets or in a lecture!
Hope this helps! Feel free to let me know if you have any further questions, I should be around on here once a week
Lancaster Physics Graduate