Modern physics covers comparatively few pages and produces a reliable number of questions, most of which follow a small set of forms. For a candidate short on time, the return per hour here is among the best in Physics.
What it actually covers
- Photoelectric effect
- Atomic structure and spectra
- Nuclear physics — binding energy, decay, half-life
- Dual nature of matter and radiation
The photoelectric effect is mostly one equation
Energy of the incident photon equals the work function plus the maximum kinetic energy of the emitted electron. Nearly every question is that relationship, rearranged.
What questions test is whether you understand the consequences: intensity changes the number of electrons, frequency changes their energy, and below the threshold frequency nothing is emitted however intense the light. That last point is where the conceptual questions live.
Half-life questions are pattern recognition
Most are answerable by counting halvings rather than by using the exponential form. After three half-lives, one-eighth remains. Recognising that turns a calculation into arithmetic you can do in your head.
Learn the exponential relation for the cases that do not fall on whole half-lives — but check first, because most exam values are chosen to be convenient.
Binding energy per nucleon explains the shape
One curve underlies fission, fusion and nuclear stability. Understanding why the curve peaks where it does means you can answer questions about all three without memorising them separately.
Where marks are lost
Unit conversions, predictably — electron volts to joules, nanometres to metres. The physics is often correct and the answer wrong by a clean power of ten, which matches a distractor.
Write the conversion explicitly rather than doing it in your head. It is the same discipline that saves marks everywhere else in Physics.