Hazards of Radiations
The increased pace of synthesis and use of radio isotopes has led to increased concern about the effect of radiations on matter, particularly in biological systems. The accident of Chernobyl occurred in 1986 in USSR is no older when radioisotopes caused a hazard there. The nuclear radiations (alpha, beta, gamma as well as X-rays) possess energies far in excess of ordinary bond energies and ionisation energies. Consequently, these radiations are able to break up and ionise the molecules present in living organisms if they are exposed to such radiations. This disrupts the normal functions of living organisms. The damage caused by the radiations, however, depends upon the radiations received. The resultant radiation damage to living system can be classified as,
(1) Somatic or pathological damage:This affects the organism during its own life time. It is a permanent damage to living civilization produced in body. Larger dose of radiations cause immediate death whereas smaller doses can cause the development of many diseases such as paralysis, cancer, leukaemia, burns, fatigue, nausea, diarrhoea, gastrointestinal problems etc. some of these diseases are fatal. Many scientists presently believe that the effect of radiations is proportional to exposure, even down to low exposures. This means that any amount of radiation causes some finite risk to living civilization.
(2) Genetic damage:As the term implies, radiations may develop genetic effect. This type of damage is developed when radiations affect genes and chromosomes, the body's reproductive material. Genetic effects are more difficult to study than somatic ones because they may not become apparent for several generations.
Tips & tricks
1. The particle like mesons, positron, neutrino, etc, about 20 in number are created by stresses in nucleus but do not exist as component of nucleus.
2. Highest degree of radioactivity is shown by radium.
3. The nuclear forces are not governed by inverse square law.
4. About 42 radioactive nuclides (Z > 82) occur in nature. Each of these gives stable end product of an isotope of lead.
5. The half life is independent of physical or chemical state of a radioactive element.
6. The average life of the natural radioactive element vary from 10–6s 1010 years or more.
7. It has been observed that fusion of 45 mg of hydrogen produce as much energy as obtained from one ton of coal.
8. Beryllium has been found to be the best moderator as it occupies small space and have low absorption cross-section.
9. The total life span of a radioactive element is infinite.
10. The g - radiation of total energy 1.02 MeV, emitted when a positron and an electron interact are known as annilation radiation.