Modern Physics means just what it says. This section concerns the areas of physics just recently discovered and not yet fully explored. The areas discussed in this section, Quantum mechanics and Nuclear physics, express ideas you may not have ever heard of before. Quantum mechanics may even seem to go against fact, and certainly against common sense. These two areas of study are on the frontiers of physics.
Nuclear energy, lasers, quantum computers, all of these things are either unperfected or exist only as a theory. Yet, with a good knowledge of modern physics, you could be the one to bring these technological advancements to the human population.