Description: After studying this lesson, you should be able to learn about,the number of neutrons and protons in nuclei of different atoms, the sizes of atomic nuclei, the nature of forces between nucleons, ‘mass defect’ and ‘binding energy’, phenomenon of radioactivity, and identify the three types of radioactive radiations, the growth and decay of radioactivity in a sample, the half-life, and decay constant of a radioactive substance, the uses of radioactivity in various fields