If you're interested in Physics there's a choice between Natural Sciences (Physical) and Mathematics. We encourage you to research both courses carefully before deciding which one to apply for.
In first year you study three experimental sciences and mathematics. In the second and third year you can concentrate solely on physics and mathematics. Although it's possible to graduate at this point, most students carry on to the optional fourth year, where you take a range of masters level courses in physics and related disciplines, do an advanced project, and get an MSci degree. See the detailed information (including course handbook) on the Physics department website.
The Maths course at Cambridge has a first year option called Maths with Physics, which may suit you if you are interested in theoretical Physics or if you are not sure whether to specialise in Physics or Maths. See the Maths with Physics leaflet for details.
After first year you may continue with Mathematics or change to second year Natural Sciences (Physical). For information about the later years of Mathematics, follow the links on the Maths department Why Study Here page.
Do bear in mind that the entry requirements for Mathematics are different to those for Natural Sciences (Physical). If you apply for Maths you will be assessed alongside other prospective maths students and if you are selected for an offer you will be asked to take STEP Papers II and III.