The becquerel (symbol Bq) is the SI derived unit The International System of Units specifies a set of seven base units from which all other units of measurement are formed. These other units are called SI derived units and are also considered part of the standard of radioactivity Radioactive decay is the process by which an unstable atomic nucleus spontaneously loses energy by emitting ionizing particles and radiation. This decay, or loss of energy, results in an atom of one type, called the parent nuclide transforming to an atom of a different type, named the daughter nuclide. For example: a carbon-14 atom emits radiation. One Bq is defined as the activity of a quantity of radioactive material in which one nucleus The nucleus is the very dense region consisting of nucleons at the center of an atom. Almost all of the mass in an atom is made up from the protons and neutrons in the nucleus, with a very small contribution from the orbiting electrons. It was discovered in 1911, as a result of Ernest Rutherford's interpretation of the famous 1909 Rutherford decays per second The second , sometimes abbreviated sec., is the name of a unit of time, and is the International System of Units (SI) base unit of time. It may be measured using a clock. The Bq unit is therefore equivalent to s The second , sometimes abbreviated sec., is the name of a unit of time, and is the International System of Units (SI) base unit of time. It may be measured using a clock−1. The becquerel is named for Henri Becquerel Antoine Henri Becquerel was a French physicist, Nobel laureate, and the discoverer of radioactivity, for which he won the 1903 Nobel Prize in Physics (along with Marie Curie and Pierre Curie who had found additional radioactive elements), who shared a Nobel Prize The Nobel Prizes are annual international awards bestowed by Scandinavian committees in recognition of cultural and scientific advances. They were established in 1895 by the Swedish chemist Alfred Nobel, the inventor of dynamite. The prizes in Physics, Chemistry, Physiology or Medicine, Literature, and Peace were first awarded in 1901. The with Pierre Pierre Curie was a French physicist, a pioneer in crystallography, magnetism, piezoelectricity and radioactivity, and Nobel laureate. In 1903 he received the Nobel Prize in Physics with his wife, Maria Skłodowska-Curie, and Henri Becquerel, "in recognition of the extraordinary services they have rendered by their joint researches on the and Marie Curie for their work in discovering radioactivity.

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 Isotopes are different types of atoms of the same chemical element, each having a different number of neutrons. In a corresponding manner, isotopes differ in mass number (or number of nucleons) but never in atomic number. The number of protons (the atomic number) is the same because that is what characterizes a chemical element. For example,, 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 The International System of Units is the modern form of the metric system and is generally a system of units of measurement devised around seven base units and the convenience of the number ten. It is the world's most widely used system of measurement, both in everyday commerce and in science 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.

The becquerel can be used for the frequency of aperiodic or stochastic events; that is, events which occur randomly and cannot be exactly predicted. For periodic events, the hertz The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of sine wave, particularly those used in radio and audio applications, which is also defined as s−1, is used as a unit.

Contents

Prefixes

As any SI unit, Bq can be prefixed The International System of Units specifies a set of unit prefixes known as SI prefixes or metric prefixes. An SI prefix is a name that precedes a basic unit of measure to indicate a decimal multiple or fraction of the unit. Each prefix has a unique symbol that is prepended to the unit symbol. The SI prefixes are standardized by the International; commonly used multiples are kBq (kilobecquerel, 103 Bq), MBq (megabecquerel, 106 Bq), GBq (gigabecquerel, 109 Bq), TBq (terabecquerel, 1012 Bq), and PBq (petabecquerel, 1015 Bq). For practical application, 1 Bq is a small unit; therefore, the prefixes are common. For example, natural potassium Potassium is the chemical element with the symbol K (Latin: kalium, from Arabic: القَلْيَه‎ al-qalyah "plant ashes" cf. Alkali from the same root, more commonly known in Modern Standard Arabic as بوتاسيوم ‹bwtasywm›), atomic number 19, and atomic mass 39.0983. Potassium was first isolated from potash. Elemental (40K) in a typical human body produces 4,000 disintegrations per second (i.e., 4 kBq of activity).[1] The nuclear explosion During the final stages of World War II in 1945, the United States conducted two atomic bombings against Japan in the cities of Hiroshima and Nagasaki in Hiroshima Hiroshima ( listen (help·info)) is the capital of Hiroshima Prefecture, and the largest city in the Chūgoku region of western Honshū, the largest island of Japan. It became the first city in history destroyed by a nuclear weapon when the United States of America dropped an atomic bomb on it at 8:15 A.M. on August 6, 1945, near the end of World (14 kt TNT equivalent is a method of quantifying the energy released in explosions. The ton of TNT is a unit of energy equal to 4.184 giga or 59 TJ) is estimated to have produced 8×1024 Bq.[2]

Bq versus counts per second

When measuring radioactivity of a sample with a detector, a unit of "counts per second" (cps) or "counts per minute" (cpm) are often used. 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.

Relationship to the curie

The curie This is roughly the activity of 1 gram of the radium isotope 226Ra, a substance studied by the pioneers of radiology, Marie and Pierre Curie, for whom the unit was named. The curie has since been replaced by an SI derived unit, the becquerel , which equates to one decay per second. Therefore: (Ci) is an older, non-SI unit of radioactivity.

The conversion factors are:

1 Ci = 3.7×1010 Bq

and

1 Bq = 2.70×10−11 Ci

Definition

1 Bq = 1 s−1

This SI The International System of Units is the modern form of the metric system and is generally a system of units of measurement devised around seven base units and the convenience of the number ten. It is the world's most widely used system of measurement, both in everyday commerce and in science unit is named after Henri Becquerel Antoine Henri Becquerel was a French physicist, Nobel laureate, and the discoverer of radioactivity, for which he won the 1903 Nobel Prize in Physics (along with Marie Curie and Pierre Curie who had found additional radioactive elements). As with every SI unit whose name is derived from the proper name of a person, the first letter of its symbol A symbol is something such as an object, picture, written word, sound, or particular mark that represents something else by association, resemblance, or convention. For example, a red octagon may be a symbol for "STOP". On maps, crossed sabres may indicate a battlefield. Numerals are symbols for numbers . All language consists of symbols is uppercase Capital letters or majuscules are the larger of two type faces in a script. In the Roman alphabet they are A, B, C, D, etc. They are also called capitals (caps) or upper case (uppercase). The latter name comes from the antique age of setting type for printing presses, when printers kept the type for these letters in the upper drawers of a desk or (Bq). When an SI unit is spelled out in English, it should always begin with a lowercase Lower case , minuscule, or small letters are the smaller form of letters, as opposed to upper case or capital letters, as used in European alphabets (Greek, Latin, Cyrillic, and Armenian). For example, the letter "a" is lower case while the letter "A" is upper case 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. Note that "degree Celsius Celsius is a temperature scale that is named after the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale two years before his death. The degree Celsius (°C) can refer to a specific temperature on the Celsius scale as well as a unit to indicate a temperature interval (a difference between two temperatures" conforms to this rule because the "d" is lowercase. —Based on The International System of Units, section 5.2.

References

  1. ^ Radioactive human body — Harvard University Natural Science Lecture Demonstrations
  2. ^ Michael J. Kennish, Pollution Impacts on Marine Biotic Communities , CRC Press, 1998, p. 74. ISBN 9780849384288.

External links

SI derived units The International System of Units specifies a set of seven base units from which all other units of measurement are formed. These other units are called SI derived units and are also considered part of the standard
Derived units The International System of Units specifies a set of seven base units from which all other units of measurement are formed. These other units are called SI derived units and are also considered part of the standard

radian The radian is the standard unit of angular measure, used in many areas of mathematics. It describes the plane angle subtended by a circular arc as the length of the arc divided by the radius of the arc. The unit was formerly a SI supplementary unit, but this category was abolished in 1995 and the radian is now considered a SI derived unit. The SI · steradian The steradian is the SI unit of solid angle. It is used to describe two-dimensional angular spans in three-dimensional space, analogous to the way in which the radian describes angles in a plane. The name is derived from the Greek stereos for "solid" and the Latin radius for "ray, beam" · hertz The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of sine wave, particularly those used in radio and audio applications · newton The newton is the SI derived unit of force, named after Isaac Newton in recognition of his work on classical mechanics · pascal The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength. It is a measure of force per unit area, defined as one newton per square metre. In everyday life, the pascal is perhaps best known from meteorological barometric pressure reports, where it occurs in the form of hectopascals (1 hPa ≡ 100 · joule The joule , named after James Prescott Joule, is the derived unit of energy in the International System of Units. It is the energy expended in applying a force of one Newton through a distance of one metre (1 Newton·metre or N·m). In terms of dimensions: · watt The watt is a derived unit of power in the International System of Units (SI), named after the Scottish engineer James Watt (1736–1819). The unit measures the rate of energy conversion. It is defined as one joule per second · coulomb The coulomb is the SI derived unit of electric charge, and is approximately equal to the charge of 6.24151 × 1018 protons or −6.24151 × 1018 electrons. It is named after Charles-Augustin de Coulomb · volt The volt is the SI derived unit of electromotive force, commonly called "voltage". It is also the unit for the related but slightly different quantity electric potential difference (also called "electrostatic potential difference"). It is named in honor of the Italian physicist Alessandro Volta (1745–1827), who invented the · farad The farad is the SI unit of capacitance. The term farad is named after the English physicist Michael Faraday · ohm The ohm is the SI unit of electrical resistance, named after Georg Simon Ohm · henry In physics, the henry is the SI unit of inductance. Originally the symbol was actually an upside down T but due to the fact no such symbol existed in standard typesets, the symbol was changed to a H. It is named after Joseph Henry (1797-1878), the American scientist who discovered electromagnetic induction independently of and at about the same · siemens The siemens is the SI derived unit of electric conductance. Siemens denote the reciprocal of resistance: one siemens is equal to the reciprocal of one ohm, and is sometimes refered to as the mho. It is named after the German inventor and industrialist Ernst Werner von Siemens. In English, the term siemens is used both for the singular and plural · weber In physics, the weber is the SI unit of magnetic flux. A flux density of one Wb/m2 (one weber per square meter) is one tesla · tesla The tesla is the SI derived unit of magnetic field B (which is also known as "magnetic flux density" and "magnetic induction"). One tesla is equal to one weber per square meter, and it was defined in 1960 in honor of the Yugoslavian-American inventor, physicist, and electrical engineer Nikola Tesla. One billionth of a tesla is · degree Celsius Celsius is a temperature scale that is named after the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale two years before his death. The degree Celsius (°C) can refer to a specific temperature on the Celsius scale as well as a unit to indicate a temperature interval (a difference between two temperatures · lumen The lumen is the SI unit of luminous flux, a measure of the power of light perceived by the human eye. Luminous flux differs from radiant flux, the measure of the total power of light emitted, in that luminous flux is adjusted to reflect the varying sensitivity of the human eye to different wavelengths of light. The lumen is defined in relation to · lux The lux is the SI unit of illuminance and luminous emittance. It is used in photometry as a measure of the intensity, as perceived by the human eye, of light that hits or passes through a surface. It is analogous to the radiometric unit watts per square metre, but with the power at each wavelength weighted according to the luminosity function, a · becquerel · gray The gray is the SI unit of absorbed radiation dose due to ionizing radiation (for example, X-rays) · sievert The sievert is the SI derived unit of dose equivalent. It attempts to reflect the biological effects of radiation as opposed to the physical aspects, which are characterised by the absorbed dose, measured in gray. It is named after Rolf Sievert, a Swedish medical physicist famous for work on radiation dosage measurement and research into the · katal The katal is the SI unit of catalytic activity. It is a derived SI unit for expressing quantity values of catalytic activity of enzymes and other catalysts. Its use is recommended by the General Conference on Weights and Measures and other international organizations. It replaces the non-SI enzyme unit. Enzyme units are, however, still more

Base units The International System of Units defines seven units of measure as a basic set from which all other SI units are derived. These SI base units and their physical quantities are:

metre The metre , symbol m, is the base unit of length in the International System of Units (SI). Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole, its definition has been periodically refined to reflect growing knowledge of metrology. Since 1983, it is defined as the distance travelled by light in · kilogram The kilogram is the base unit of mass in the International System of Units (SI, from the French Le Système International d’Unités),[Note 2] which is the modern standard governing the metric system. The kilogram is defined as being equal to the mass of the International Prototype Kilogram (IPK),[Note 3] which is almost exactly equal to the mass · second · ampere · kelvin · candela · mole

Categories: SI derived units | Units of radioactivity | Units of frequency

 

The above information uses material from Wikipedia and is licensed under the GNU Free Documentation License.
Some facts may not have been fully verified for accuracy. [Disclaimers]
This page was last archived by our server on Thu Sep 2 21:39:27 2010. [ refresh local cache ]
Displaying this page or its contents does not use any Wikimedia Foundation's resources.
The owners of this site proudly support the Wikimedia Foundation.


- The Necklace written by Guy de Maupassant becquerel IV version ...
icefootprints.multiply.com
- The Necklace written by Guy de Maupassant becquerel IV version ...

unknown

Sat, 30 Jun 2007 09:57:16 GM

Video, The Necklace written by Guy de Maupassant . becquerel. IV version ue part 2, Jun 30, '07 5:57 AM for everyone. enjoy guys.. :D. Download this and other original video files with Multiply Premium. Prev: The Necklace written by Guy ...

Google Blogs Search: Becquerel,
Mon Sep 6 02:58:28 2010