Becquerel

The becquerel (symbol: Bq) is the SI unit of radioactivity.

Explanation

The becquerel (symbol Bq) is the SI derived unit of radioactivity, defined as the activity of a quantity of radioactive material in which one nucleus decays per second. It is therefore equivalent to s-1. The older unit of radioactivity was the curie (Ci), defined as 3.7×1010 becquerels or 37 GBq.

Related Topics:
SI derived unit - Radioactivity - Activity - Nucleus - Second - Curie

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In a fixed mass of radioactive material, the number of becquerels changes with time. In some circumstances, amounts of radioactive material are given after adjustment for some period of time. For example, one might quote a ten-day adjusted figure, that is, the amount of radioactivity that will still be present after ten days. This deemphasizes short-lived isotopes.

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It was designated, in the SI, to use the becquerel rather than the reciprocal second for the activity measure unit. This unit was specifically introduced because of the dangers to human health which might arise from mistakes involving the units reciprocal second. Using the becquerel unit a more active source (and so, all the other things fixed, more dangerous) has an higher number. Using 1/s or s as a second may instead lead to confusion.

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