Radioactivity

Diagram 3 shows the activity-time graph of radioisotope Potassium-42. This radioisotope emits beta particles and is used as a tracer to measure the quantity of salt in human body. State one characteristic of beta particles. [1 mark] Based on Diagram 3 , determine the half-life of Potassium-42. Show on the graph how you determine the … Read more

Nuclear Reactor A nuclear reactor produces tremendous amount of energy through nuclear fission. The energy liberated from the fusion of nuclear fuel heats the surrounding water. As a result, steam is generated to drive turbines, which in turn drive the electrical generators. The main components of a nuclear reactor: Graphite moderatorFast moving neutrons are slowed … Read more

Nuclear Fusion In nuclear fusion, two or more small and light nuclei come together to form a heavier nucleus. This process is accompanied by the release of a huge amount of energy. Below are two examples of fusion reactions: Fusion is much more difficult to achieve than fission because the hydrogen nuclei repel each other. … Read more

Chain Reaction If neutrons from the fission of uranium-235 continue to split other nuclei causing further fission, a chain reaction has occurred. The number of nuclei which undergo fission multiplies rapidly. In order for a chain reaction to take place, a minimum of one neutron from each fission must trigger further fission. At the same … Read more

Nuclear Reaction In a nuclear reaction, the mass of the parent particles will become less (know as mass defect). The defected mass is then converted into energy called the nuclear energy. In short, nuclear energy is the energy released owing to the defect of mass in a nuclear reaction. There are 2 types of nuclear … Read more

Nuclear Energy In a radioactive decay, one element changes into another in a process called transmutation. The mass of the daughter particles are less than that of the parent particle. This difference in mass is called mass defect or mass loss. Mass defect is the missing mass in a nuclear reaction and the missing mass … Read more

Uses of Radioisotope in Agriculture Pest Control Male insect is sterilised by exposing to radioactive radiation and then released back to the ecosystem. This can ensure that their reproducing effort do not generate new generation and hence reduces the population of the insect. Tracer The metabolism of phosphorus by plants can be studied using phosphate … Read more

Uses of Radioisotope in Medical Radiotherapy Gamma rays of cobalt-60 can be used to destroy cancer cells in patients. This treatment is known as radiotherapy. Tracer to Detect Blood Clots or Tumour A small amount of sodium-24 is injected into the patient’s body.  Radioactive imaging is then used to detect accumulation of sodium-24 and therefore … Read more

Series Decay Sometimes after a radioactive decay, the daughter nuclide formed is still unstable. It will further decay into another nuclide which may also unstable. This process continues until a stable nuclide is reached. This is called a series decay. Each decay will emit either an alpha particle or a beta particle and may be … Read more