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half life

/ˈhɑːf ˌlaɪf/

1 entry

phrase

/ˈhɑːf ˌlaɪf/C1formalscientific
  • ruВремя, необходимое для того, чтобы количество (например, радиоактивного вещества, лекарства в организме или химической реакции) уменьшилось вдвое от своего первоначального значения. Также используется метафорически для описания скорости убывания или распада чего-либо с течением времени.

The time required for a quantity (such as a radioactive substance, a drug in the body, or a chemical reaction) to reduce to half its initial value. Also used metaphorically to describe the rate of decline or decay of something over time.

  1. Radioactive decayC1formal

    The time required for a quantity of a radioactive substance to reduce to half of its initial value.

    ruПериод полураспада

    • The half-life of carbon-14 is about 5,730 years.
    • Scientists use half-life to date ancient artifacts.
    • Uranium-238 has a half-life of 4.5 billion years.
  2. Chemical eliminationC1formal

    The time it takes for the concentration of a substance (e.g., a drug) in the body to decrease by half.

    ruПериод полувыведения

    • The drug has a half-life of approximately 12 hours.
    • Doctors consider the half-life when prescribing medication.
    • The half-life of caffeine in the human body is about 5 hours.