PHYSICS IN FOCUS.

The article focuses on the dual nature of radiation and matter, particularly through the lens of the photoelectric effect and the principles of quantum mechanics. It explains the photoelectric effect as the emission of electrons from metal surfaces when exposed to light of suitable frequency, emphasizing that this phenomenon is a one photon-one electron interaction. The article also discusses the relationship between photoelectric current and factors such as light intensity and frequency, introducing Einstein's photoelectric equation, which relates photon energy to the kinetic energy of emitted electrons. Additionally, it covers de Broglie's hypothesis of matter waves, the structure of the atom as described by Rutherford and Bohr, and the concepts of nuclear fission and fusion, highlighting the binding energy and mass-energy equivalence as fundamental principles in nuclear physics. [Extracted from the article]