Does anyone know how much of the preliminary topics are in the HSC. I have heard from people that 20% of the HSC is prelim work but the recent trials i did didnt seem to have any prelim.
Technically none. That said, there will always be some carried over and it is assumed knowledge all of it. You will find that, especially in the sciences, that the most skills and content will be carried across into your HSC year.
You use a bit of v=f(lamda) in the Black body radiation section, P=VI in the transformers section, the three eaquations of motion are used in Projectile motion and you also use the centripetal force equation. If you do astrophysics as an option there is alos a little bit of overlap with Cosmic engine.