I personally found it very very difficult because of the sheer volume of things we had to know. Unlike Maths where the questions were mostly repeatable with different values etc. The problem I found I had was thinking if I just knew the equations/facts that I would be able to answer the questions, but knowing how to apply your knowledge is very important (which is why I'm going to be happy with anything over a U with how much I struggled the second year, but with more practice rather than just looking at the notes I know I could've done better).
As for what's on the specification, I don't know if it will be the same, but in the first year we did:
- Quantum Phenomena (e.g. the Photoelectric Effect/Photons/Energy Levels)
- Electricity (e.g. Circuits/IV characteristics/Resistivity/EMF and internal resistance/Kirchhoff's Laws)
- Particles and Radiation (e.g. Atom constituents/Nuclei Stability/Classification of particles and antiparticles/Strong and weak nuclear force)
- Mechanics (e.g. Scalars and Vectors/Moments/Newton's laws of motion/Linear motion and non-uniform acceleration)
- Waves (e.g. Progressive and Stationary waves/Superposition/Interference, Diffraction and Refraction)
In the second year:
- Circular Motion and Simple Harmonic Motion (e.g. Resonance/Angular Speed/Centripetal Force and Acceleration)
- Gravitational Fields (e.g. Gravitational force/field strength/satellite and planet orbits)
- Electric Fields (e.g. Electrostatic force and electric potential)
- Magnetic Fields (e.g. Magnetic flux density/Magnetic flux/Electromagnetic induction/Transformers)
- Thermal Physics (e.g. Ideal Gases/Molecular Kinetic Theory model)
- Nuclear Physics (e.g. Rutherford Scattering/Nuclear mass and energy)
- Capacitance (how capacitors work/charging and discharging etc.)
- Astrophysics (though the last topic is chosen from a selection by the college so I would not look this up unless you know it's on the specification)