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Radiation is often categorized as either ionizing or non-ionizing depending on the energy of the radiated particles. Ionizing radiation carries more than 10 electron volts (eV), which is enough to ionize atoms and molecules and break chemical bonds. This is an important distinction due to the large difference in harmfulness to living organisms.
Radiation protection, also known as radiological protection, is defined by the International Atomic Energy Agency (IAEA) as "The protection of people from harmful ...
[6] [7] [8] Quizlet's blog, written mostly by Andrew in the earlier days of the company, claims it had reached 50,000 registered users in 252 days online. [9] In the following two years, Quizlet reached its 1,000,000th registered user. [10] Until 2011, Quizlet shared staff and financial resources with the Collectors Weekly website. [11]
Radiation is a moving form of energy, classified into ionizing and non-ionizing type. [4] Ionizing radiation is further categorized into electromagnetic radiation (without matter) and particulate radiation (with matter). [4] Electromagnetic radiation consists of photons, which can be thought of as energy packets, traveling in the form of a wave ...
The adoption of the gray by the 15th General Conference on Weights and Measures as the unit of measure of the absorption of ionizing radiation, specific energy absorption, and of kerma in 1975 [17] was the culmination of over half a century of work, both in the understanding of the nature of ionizing radiation and in the creation of coherent ...
In electromagnetic radiation (such as microwaves from an antenna, shown here) the term radiation applies only to the parts of the electromagnetic field that radiate into infinite space and decrease in intensity by an inverse-square law of power, such that the total energy that crosses through an imaginary sphere surrounding the source is the ...
Likewise, gamma radiation and X-rays were found to be high-energy electromagnetic radiation. The relationship between the types of decays also began to be examined: For example, gamma decay was almost always found to be associated with other types of decay, and occurred at about the same time, or afterwards.
Natural background radiation comes from five primary sources: cosmic radiation, solar radiation, external terrestrial sources, radiation in the human body, and radon. The background rate for natural radiation varies considerably with location, being as low as 1.5 mSv/a (1.5 mSv per year) in some areas and over 100 mSv/a in others.