Topics: Waves, optics, Modern Physics, Wave-forms, Stationary Waves, Wave Speed, Transfer of Wave Energy, Wave Energy, Periodic Sound Wave, resonance, sound wave, musical note, Doppler Effect, Refraction, Law of Refraction, Apparent Depth, Total Internal Reflection, mirror, lens, Optical Formula, thin lens, Optical Instrument, Lens Aberration, Dispersive Power, atomic models, Atomic Structure, electron, atomic model, Discovery of Electron, hydorgen spectrum, Bohr's model of atom, Bohr's quantum condition, Electron Cloud Model, Wave-Particle Duality of Light, Wave-Particle Duality, X-Ray Production, Nuclear stability, Radioactivity, Ionizing Radiation, Radioactive Decay equation, half-life, Mean Life Time