ABSTRACT
This chapter discusses the important concepts of special relativity, wave-particle duality, and quantum mechanics. The classical laws of dynamics as developed by Newton were believed, for over 200 years, to describe all motion in nature. Students still spend considerable effort mastering the use of these laws of motion. The structure of the nucleus of an atom has now also been well developed qualitatively and is supported by a wealth of nuclear data. Nuclear reactions play a very important role in many areas of nuclear science and engineering, because it is through such reactions that various types of radiation are produced. Radioactive nuclei and their radiations have properties that are the basis of many of the ideas and techniques of atomic and nuclear physics. The discovery of artificial, or induced, radioactivity started a new line of nuclear research and hundreds of artificial nuclei have been produced by many different nuclear reactions.
