Explain ionizing and non-ionizing radiations.
Answers
Explanation:
The region at which radiation is considered "ionizing" is not well defined, since different molecules and atoms ionize at different energies. The usual definitions have suggested that radiation with particle or photon energies less than 10 electronvolts (eV) be considered non-ionizing. Another suggested threshold is 33 electronvolts, which is the energy needed to ionize water molecules. The light from the Sun that reaches the earth is largely composed of non-ionizing radiation, since the ionizing far-ultraviolet rays have been filtered out by the gases in the atmosphere, particularly oxygen. The remaining ultraviolet radiation from the Sun causes molecular damage (for example, sunburn) by photochemical and free-radical-producing means.[citation needed]
Different biological effects are observed for different types of non-ionizing radiation.[2][3][4] The upper frequencies of non-ionizing radiation near these energies (much of the spectrum of UV light and some visible light) are capable of non-thermal biological damage, similar to ionizing radiation. Health debate therefore centers on the non-thermal effects of radiation of much lower frequencies (microwave, millimetre and radiowave radiation). The International Agency for Research on Cancer recently stated that there could be some risk from non-ionizing radiation to humans.[5] But a subsequent study reported that the basis of the IARC evaluation was not consistent with observed incidence trends.[6] This and other reports suggest that there is virtually no way that results on which the IARC based its conclusions are correct.[7]