Definition of radioactivity in English:



mass noun
  • 1The emission of ionizing radiation or particles caused by the spontaneous disintegration of atomic nuclei.

    • ‘Pierre and Marie Curie called Becquerel's radiation radioactivity.’
    • ‘TL is based on the continual accumulation of stored energy as a function of natural radioactivity.’
    • ‘The results also point the way to the first direct measurements of the total radioactivity of the earth.’
    • ‘The Curies resolved to learn as much as they could about the source of radioactivity in pitchblende, the ore with which Becquerel originally worked.’
    • ‘The idea that radioactive isotopes can be used for dating purposes is almost as old as Henri Becquerel's discovery of radioactivity itself in 1896.’
    • ‘This year is the centennial of the Nobel Prize in Physics shared by Henri Becquerel and the Curies for their pioneering work on radioactivity.’
    • ‘A station opened in the Chatham Islands to monitor radioactivity, will help police the worldwide ban on Nuclear Weapons Testing.’
    • ‘What makes dirty bombs particularly troublesome is that radioactivity, like fire, is something we deal with on a daily basis.’
    • ‘Indeed, many isotopes spontaneously convert to other elements through radioactivity.’
    • ‘Their temperature ranges between 27°C and 51°C and they vary in radioactivity and fluorine content.’
    • ‘In the first five years, the reactors will undergo mild surface-level deactivation to minimize their radioactivity.’
    • ‘Early studies of radioactivity revealed that certain atomic nuclei were naturally radioactive.’
    • ‘Each appropriate region was scraped individually and radioactivity was determined in a scintillation counter.’
    • ‘The time interval needed to reduce the applied radioactivity to 50% was taken as the optimal pulsing time.’
    • ‘The element itself was actively producing radiation, a property referred to as radioactivity.’
    • ‘When this occurs, the electron shoots out of the atom and is called a beta particle, a type of radioactivity.’
    • ‘In 1899 he identified two forms of radioactivity, which he called alpha and beta particles.’
    • ‘The Bequerel is a unit of radioactivity, which is equivalent to the number of radioactive particles detected per second.’
    • ‘The becquerel is a unit of radioactivity and corresponds to one radioactive disintegration per second.’
    • ‘They may also interact with nonmedical regulations, such as limits on electromagnetic emissions or radioactivity.’
    1. 1.1 Radioactive substances, or the radiation emitted by these.
      ‘an escape of radioactivity’
      • ‘One example he gave was the leakage of radioactivity from Sellafield caused by pigeons.’
      • ‘Scientists can compare the number of breakdowns in any given time and the intensity of the radioactivity among elements and isotopes.’
      • ‘Small amounts of radioactivity escaped into the atmosphere.’
      • ‘The accident, which didn't cause any leakage of radioactivity, occurred when the train was reversing at just 5mph.’
      • ‘The most common ill effects of exposure to radioactivity result from the ionization of water molecules by the radiation.’
      • ‘Over the six decades of the lab's operation, radioactivity has leaked in unknown quantities into the water and vegetation surrounding the facility.’
      • ‘The NRC says, even if a plane did attack a nuclear plant the likelihood of releasing radioactivity is low.’
      • ‘The technique is based on the detection of radioactivity emitted after a small amount of a radioactive tracer is injected into a peripheral vein.’
      • ‘Cattle seem to absorb less radioactivity than sheep, except for the milk, which is to be avoided at all costs because of the iodine.’
      • ‘Its functions relate principally to the monitoring of radioactivity in the environment and of radiation doses received by Irish people in the course of their work.’
      • ‘So sensitive is the detector that a single speck of dust within it could emit enough natural radioactivity to queer the readings.’
      • ‘No access to the core is possible because of the levels of radioactivity, continuing high temperatures inside and fears about its stability.’
      • ‘They are comparing sediment taken from the Humber estuary - unpolluted by radioactivity - with other samples which contain the substance.’
      • ‘The 60 cities with federally reported dietary levels of radioactivity are often not proximate to nuclear sites.’
      • ‘The lack of safeguards is leaving thousands of children across central Scotland at risk of thyroid cancer following an escape of radioactivity.’
      • ‘In the event of slow release of radioactivity it would be particularly important that medical personnel could recognise and diagnose the early effects of radiation.’
      • ‘The devices could be equipped with sensors that detect various substances, from heat to chemicals or radioactivity.’
      • ‘Similar dangers exist of a structural collapse leading to an uncontrollable release of energy which could release radioactivity, he said.’
      • ‘It is suspected that workers have brought home tiny particles of radioactivity attached to their clothing or their skin.’
      • ‘He is one of nine authorities which have been supplied with the latest equipment for recording and detecting radioactivity after an atomic bomb explosion.’