Go to a bookshop. Spend 60 RON. Hold the physical "Culegere" in your hands. The smell of the paper, the ability to write in the margins, and the satisfaction of crossing off solved problems are irreplaceable.
A common mistake is jumping to the hardest problems. Master first. If you cannot solve the first 10 problems of thermodynamics without looking at the formula sheet, you are not ready for Level II. Mihaela Chirita Culegere Fizica Clasa 11 Pdf - Google
The problems are designed to match the level of difficulty found in national exams. Guide to Using "Culegere Fizica Clasa 11" by