It varies to some extent depending on which board you can do. I tutored Edexcel A-level last year and this was pretty much what was covered:
AS physics was mechanics, materials, fluids, electricity, waves, quantum physics
A2 physics was further mechanics (circular motion, gravitation, momentum, oscillations and SHM), electric fields, capacitors, electromagnetic induction, particle physics, astrophysics, nuclear physics and thermodynamics.
Best thing to do is look at the new A-level specifications for any of the exam boards, they will be more similar than they are different.