Encouraged by the response to the first edition and based on the suggestions received, the author has included seven new topics in this Second Edition. Beginning with the fundamental principles like Thermionic emission, Photoelectric effect, Thermo electric effect, this textbook covers advanced topics like Acoustics, Ultrasonics, Laser, Holography (3-dimensional Photography), Fiber Optics Communication, Electron Microscope, Quantum Physics and Schrodinger Wave Equation, Superconductivity, Birefringence, Electro-optic effect, Photo-elasticity etc. Band theory in solids, technical aspects and applications of Semiconductor Devices, Transistors, C.R.O. are explained along with the Crystal Structure. Other topics include process of formation of Colors in the thin film, Diffraction, Polarization, High-energy particle accelerator, Mass Spectrograph, Nuclear Reactor, and underlying process behind nuclear explosions.