At the end of the 19-th century, physics was at its most confidence situation. Classical phyics, as formulated in Newton’s law of mechanics and Maxwell’s theory of electromagnetism, have proved very successful in solving every problem. →At that time there seemed to be no question for which physics could not provide an answer !!! But then it came as a great shock when some simple phenomena were observed which could not be explained by classical physics →a new theory, quantum theory, was developed at the beginning of the 20-th century. | f EKICDAI DUVQICQ GENERAL rnTOiCo III Optics Quantum Physics Chapter XX Quantum theory of light 1. Blackbody radiation. Planck s theory of radiation 2. Photoelectric effect. Einstein s theory of light 3. Compton scattering At the end of the 19-th century physics was at its most confidence situation. Classical phyics as formulated in Newton s law of mechanics and Maxwell s theory of electromagnetism have proved very successful in solving every problem. At that time there seemed to be no question for which physics could not provide an answer But then it came as a great shock when some simple phenomena were observed which could not be explained by classical physics a new theory quantum theory was developed at the beginning of the 20-th century We begin our study of quantum physics by two following phenomena Blackbody radiation Photoelectric effect We will see what were the failures of classical physics and how a new theory had been .