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Physical Chemistry

Becquerel

Definition and meaning of Becquerel in chemistry.

The becquerel is the SI unit of radioactivity, equal to one radioactive decay event per second.

In more detail

Named after French physicist Henri Becquerel, who discovered radioactivity in 1896, the becquerel quantifies the rate at which unstable atomic nuclei decay. Used extensively in nuclear medicine, radiation protection, and environmental monitoring, it provides a precise measurement of radioactive source strength. The older unit, the curie (Ci), remains in some applications; 1 curie equals 37 billion becquerels.

Key facts

SymbolBq
Definition1 radioactive decay per second
Named afterHenri Becquerel (1852–1908)
FieldPhysical Chemistry
Example

A technetium-99m radiopharmaceutical used in medical imaging might have an activity of 750 megabecquerels (750 MBq) when administered to a patient for a cardiac scan.

Frequently asked questions

How does the becquerel relate to the older curie unit?

The curie (Ci) is an older unit of radioactivity; 1 Ci = 3.7 × 10^10 Bq (37 billion becquerels).

Is becquerel the same as gray or sievert?

No, the becquerel measures the rate of radioactive decay (activity), while gray and sievert measure the amount of radiation absorbed or its biological effect.

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