Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
A sievert (Sv) is the SI unit used to measure the biological effect of ionizing radiation on human tissue. It quantifies the risk of radiation exposure by considering both the dose and its impact on different types of tissues.
5 Must Know Facts For Your Next Test
1 Sv is equivalent to 1 joule per kilogram (J/kg) in terms of absorbed energy.
The sievert takes into account the type of radiation and its biological effects, using weighting factors.
Radiation doses are often expressed in millisieverts (mSv), where 1 Sv = 1000 mSv.
Occupational exposure limits for radiation workers are typically around 50 mSv per year.
Acute exposure to high levels of radiation, above several sieverts, can be fatal.
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Related terms
Gray (Gy): The SI unit that measures the absorbed dose of ionizing radiation, equal to one joule per kilogram.
Rad: An older unit of absorbed dose of ionizing radiation, where 1 rad = 0.01 Gray.
Rem: A non-SI unit for measuring biological effect of ionizing radiation, where \(1 \text{rem} = \frac{1}{100} \text{Sv}\).