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. SI derived units are part of the SI system of measurement units and are derived from the seven SI base units They are derived from SI basic units/defined Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. Radioactive decay is the process in which an unstable Atomic nucleus loses energy by emitting ionizing particles and Radiation. The nucleus of an Atom is the very dense region consisting of Nucleons ( Protons and Neutrons, at the center of an atom The second ( SI symbol s) sometimes abbreviated sec, is the name of a unit of Time, and is the International System of Units It is therefore equivalent to s^-1. The second ( SI symbol s) sometimes abbreviated sec, is the name of a unit of Time, and is the International System of Units The becquerel is named for Henri Becquerel, who shared a Nobel Prize with Pierre and Marie Curie for their work in discovering radioactivity. Antoine Henri Becquerel (15 December 1852 &ndash 25 August 1908 was a French Physicist, Nobel laureate, and one of the discoverers of Radioactivity The Nobel Prize (Nobelpriset (Nobelprisen is a Swedish prize established in the 1895 will of Swedish chemist Alfred Nobel; it was first awarded in Peace, Literature Pierre Curie (15 May 1859 &ndash 19 April 1906 was a French physicist, a pioneer in Crystallography, Magnetism, Piezoelectricity

In a fixed mass of radioactive material, the number of becquerels changes with time. Therefore, a sample radioactive decay rate is always stated with a timestamp for short-lived isotopes, sometimes after adjustment to some specific date of interest (in the past or in the future). For example, one might quote a ten-day adjusted figure, that is, the amount of radioactivity that will still be present ten days in the future. This can de-emphasize short-lived isotopes.

SI uses the becquerel rather than the second for the unit of activity measure to avoid dangerous mistakes: a measurement in becquerels is proportional to activity, and thus a more dangerous source of radiation gives a higher reading. A measurement in seconds is inversely proportional. As any SI unit, Bq can be prefixed; commonly used multiples are kBq (kilobecquerel, 10³ Bq), MBq (megabecquerel, 10⁶ Bq), and GBq (gigabecquerel, 10⁹ Bq). An SI prefix (also known as a metric prefix) is a name or associated symbol that precedes a unit of measure (or its symbol to form a Decimal multiple or

When measuring radioactivity of a sample with a detector, a unit of "counts per second" (cps) or "counts per minute" (cpm) are often used. Counts per minute (cpm is a measure of Radioactivity. It is the number of Atoms in a given quantity of radioactive material that are detected to have These units can be converted to the absolute activity of the sample in Bq if one applies a number of significant conversions, e. g. , for the radiation background, for the detector efficiency, for the counting geometry, for self-absorption of the radiation in the sample.

The becquerel can be used for the frequency of aperiodic events; for periodic events, the hertz, which is also defined as s^–1, is used as unit. The hertz (symbol Hz) is a measure of Frequency, informally defined as the number of events occurring per Second.

Relationship to the curie

The curie (Ci) is an older, non-SI unit, of radioactivity. A CURIE (short for Compact URI) is an abbreviated URI expressed in CURIE syntax and may be found in both XML and non-XML grammars It is equivalent to 3. 70 × 10¹⁰ disintegrations per second, which is approximately the amount of activity produced by 1 g of radium-226. Thus the curie is defined as 3. 7×10¹⁰ becquerels or 37 GBq.

Definition

1 Bq = 1 s^–1

This SI unit is named after Henri Becquerel. Antoine Henri Becquerel (15 December 1852 &ndash 25 August 1908 was a French Physicist, Nobel laureate, and one of the discoverers of Radioactivity As with every SI unit whose name is derived from the proper name of a person, the first letter of its symbol is uppercase (Bq). The musical instrument is spelled Cymbal. A symbol is something --- such as an object, Picture, written word a sound a piece Capital letters or majuscules pronunciation /məˈdʒʌskyuls ˈmædʒəˌskyuls/ in the Roman alphabet A, B, C, D, When an SI unit is spelled out in English, it should always begin with a lowercase letter (becquerel), except where any word would be capitalized, such as at the beginning of a sentence or in capitalized material such as a title. Lower case (also lower-case or lowercase) minuscule, or small letters are the smaller form of letters as opposed to upper Note that "degree Celsius" conforms to this rule because the "d" is lowercase. The Celsius Temperature scale was previously known as the centigrade scale. — Based on The International System of Units, section 5. 2.

External links

• Derived units on the BIPM web site

The International Bureau of Weights and Measures ( Bureau international des poids et mesures, in French) is an international Standards organization, one

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