Explain me modern physics in an easiest way and what are the sub topics in it ?

Modern physics is a branch of physics that deals the topic where matter and energy are not separate, but it is an alternate form of each other. It is based on the two major breakthroughs of twentieth century: relativity and quantum mechanics

Some major topics in Modern physics

• Atomic theory and the evolution of the atomic model in general
• Black Body radiation
• Franck–Hertz experiment
• Geiger–Marsden experiment (Rutherford’s experiment)
• Gravitational lensing
• Michelson–Morley experiment
• Photoelectric effect
• Quantum thermodynamics
• Radioactive phenomena in general
• Perihelion precession of Mercury
• Stern–Gerlach experiment
• Wave–particle duality
• Solid