WAEC Physics 2010 Theory — Question 12

Model answer

²²⁶₈₈Ra → ²²²₈₆Rn + ⁴₂α represents a natural radioactivity decay (alpha decay occurring spontaneously). ¹⁴₇N + ⁴₂α → ¹⁷₈O + ¹₁P represents an artificial radioactivity decay (induced by bombarding nitrogen with an alpha particle). Difference between Natural and Artificial Radioactivity: (1) Natural radioactivity is a spontaneous disintegration of atomic nuclei of an element, while artificial radioactivity is achieved by bombarding a non-radioactive element with a particle e.g. neutron, proton, alpha particle etc. (2) In natural radioactivity, the alpha particle is a by-product, while it is used as a bombarding particle in artificial radioactivity. (3) Heavy nuclei are involved in natural radioactivity, but in artificial radioactivity, light atoms are also involved.