The United States Navy & United States Coast Guard occupational rating of gunner's mate is a designation given by the Bureau of Naval Personnel to enlisted sailors who either satisfactorily complete initial Gunner's Mate "A" school training, or who "strike" for the rating by showing competence in the field of ordnance. When "striking" one isn't required to be a seaman, but must belong to one of three undesignated rates: Fireman, Seaman, or Airman, it is possible cross rate to Gunner's Mate. Cross rating refers to the act of an enlisted sailor "crossing" from their current rating to another rating of their choice, provided their ASVAB scores are high enough and there are open slots for the rate; the Gunner's Mate "A" school is held at Naval Training Center Great Lakes and Yorktown, VA for the USCG. In its early years, the school was hands-on, but it is now conducted through technical educational tools, such as self-study computer-based training. Training focuses on the operation and troubleshooting of naval guns, missile launchers and torpedoes as well as a strong emphasis on basic explosives and tracking systems, small arms, Naval ammunition classification, safety.
Upon completion of this basic training, enlisted members continue on to a specialized "C" school, where they learn a particular weapons system. A GM will specialize in a multitude of weapons varieties; as well as this, GMs care for and assist in operating shooting ranges and the storage and maintenance of arms. On February 26, 2007 the Chief of Naval Operations approved the merger of the gunner’s mate and torpedoman’s mate ratings into the GM rating; the move was made to leverage the strengths, knowledge and abilities found in the two ratings to meet current and future strategic mission needs. “The training sailors receive after basic training for their ratings on an apprentice level has been the same for both gunner's and torpedomen's mates,” said Senior Chief Torpedoman's Mate, Sherry Secrease of the Navy Personnel Command. “This makes the merger easier to accomplish.”The Gunner's Mate rating is surface warfare-based. Associated Naval occupational ratings are Fire Controlman, Aviation Ordnanceman, Missile Technician, Mineman.
The Gunner's Mate rating is one of the original ratings created as a result of the Naval Armament Act of 1794. The others include Boatswain's Mate, Master-at-Arms, Yeoman; the rating is among the top five source ratings for enlisted Naval Special Warfare candidates. GM from Navy Personnel Command: Bureau of Naval Personnel Enlisted Ratings and Jobs in the US Navy Navy Ratings and present Navy Speciality ratings & Emergency ratings CNRC Fact Sheet for the GM rating
The gram is a metric system unit of mass. Defined as "the absolute weight of a volume of pure water equal to the cube of the hundredth part of a metre, at the temperature of melting ice". However, in a reversal of reference and defined units, a gram is now defined as one thousandth of the SI base unit, the kilogram, or 1×10−3 kg, which itself is now defined by the International Bureau of Weights and Measures, not in terms of grams, but by "the amount of electricity needed to counteract its force" The only unit symbol for gram, recognised by the International System of Units is "g" following the numeric value with a space, as in "640 g" to stand for "640 grams" in the English language; the SI does not support the use of abbreviations such as "gr", "gm" or "Gm". The word gramme was adopted by the French National Convention in its 1795 decree revising the metric system as replacing the gravet introduced in 1793, its definition remained that of the weight of a cubic centimetre of water. French gramme was taken from the Late Latin term gramma.
This word—ultimately from Greek γράμμα, "letter"—had adopted a specialised meaning in Late Antiquity of "one twenty-fourth part of an ounce", corresponding to about 1.14 modern grams. This use of the term is found in the carmen de ponderibus et mensuris composed around 400 AD. There is evidence that the Greek γράμμα was used in the same sense at around the same time, in the 4th century, survived in this sense into Medieval Greek, while the Latin term did not remain current in Medieval Latin and was recovered in Renaissance scholarship; the gram was the fundamental unit of mass in the 19th-century centimetre–gram–second system of units. The CGS system co-existed with the MKS system of units, first proposed in 1901, during much of the 20th century, but the gram has been displaced by the kilogram as the fundamental unit for mass when the MKS system was chosen for the SI base units in 1960; the gram is today the most used unit of measurement for non-liquid ingredients in cooking and grocery shopping worldwide.
Most standards and legal requirements for nutrition labels on food products require relative contents to be stated per 100 g of the product, such that the resulting figure can be read as a percentage by weight. 1 gram = 15.4323583529 grains 1 grain = 0.06479891 grams 1 avoirdupois ounce = 28.349523125 grams 1 troy ounce = 31.1034768 grams 100 grams = 3.527396195 ounces 1 gram = 5 carats 1 gram = 8.98755179×1013 joules 1 undecimogramme = 1 "eleventh-gram" = 10−11 grams in the historic quadrant–eleventh-gram–second system a.k.a. hebdometre–undecimogramme–second system 500 grams = 1 Jin in the Chinese units of measurement. 1 gram is equal to 1 small paper clip or pen cap. The Japanese 1 yen coin has a mass of one gram, lighter than the British penny, the United States cent, the Euro cent, the 5 cent Australian coins. Conversion of units Duella Gold gram Orders of magnitude Gram at Encyclopædia Britannica
The Geiger–Müller tube or G–M tube is the sensing element of the Geiger counter instrument used for the detection of ionizing radiation. It was named after Hans Geiger, who invented the principle in 1908, Walther Müller, who collaborated at University of Kiel with Geiger in developing the technique further in 1928 to produce a practical tube that could detect a number of different radiation types, it is a gaseous ionization detector and uses the Townsend avalanche phenomenon to produce an detectable electronic pulse from as little as a single ionising event due to a radiation particle. It is used for the detection of gamma radiation, X-rays, alpha and beta particles, it can be adapted to detect neutrons. The tube operates in the "Geiger" region of ion pair generation; this is shown on the accompanying plot for gaseous detectors showing ion current against applied voltage. While it is a robust and inexpensive detector, the G–M is unable to measure high radiation rates efficiently, has a finite life in high radiation areas and cannot measure incident radiation energy, so no spectral information can be generated and there is no discrimination between radiation types.
A G-M tube consists of a chamber filled with a gas mixture at a low pressure of about 0.1 atmosphere. The chamber contains two electrodes, between which there is a potential difference of several hundred volts; the walls of the tube are either metal or have their inside surface coated with a conducting material or a spiral wire to form the cathode, while the anode is a wire mounted axially in the centre of the chamber. When ionizing radiation strikes the tube, some molecules of the fill gas are ionized directly by the incident radiation, if the tube cathode is an electrical conductor, such as stainless steel, indirectly by means of secondary electrons produced in the walls of the tube, which migrate into the gas; this creates positively charged free electrons, known as ion pairs, in the gas. The strong electric field created by the voltage across the tube's electrodes accelerates the positive ions towards the cathode and the electrons towards the anode. Close to the anode in the "avalanche region" where the electric field strength rises exponentially as the anode is approached, free electrons gain sufficient energy to ionize additional gas molecules by collision and create a large number of electron avalanches.
These spread along the anode and throughout the avalanche region. This is the "gas multiplication" effect which gives the tube its key characteristic of being able to produce a significant output pulse from a single original ionising event. If there were to be only one avalanche per original ionising event the number of excited molecules would be in the order of 106 to 108; however the production of multiple avalanches results in an increased multiplication factor which can produce 109 to 1010 ion pairs. The creation of multiple avalanches is due to the production of UV photons in the original avalanche, which are not affected by the electric field and move laterally to the axis of the anode to instigate further ionising events by collision with gas molecules; these collisions produce further avalanches, which in turn produce more photons, thereby more avalanches in a chain reaction which spreads laterally through the fill gas, envelops the anode wire. The accompanying diagram shows this graphically.
The speed of propagation of the avalanches is 2–4 cm per microsecond, so that for common sizes of tubes the complete ionisation of the gas around the anode takes just a few microseconds. This short, intense pulse of current can be measured as a count event in the form of a voltage pulse developed across an external electrical resistor; this can be in the order of volts. The discharge is terminated by the collective effect of the positive ions created by the avalanches; these ions have lower mobility than the free electrons due to their higher mass and move from the vicinity of the anode wire. This creates a "space charge" which counteracts the electric field, necessary for continued avalanche generation. For a particular tube geometry and operating voltage this termination always occurs when a certain number of avalanches have been created, therefore the pulses from the tube are always of the same magnitude regardless of the energy of the initiating particle. There is no radiation energy information in the pulses which means the Geiger–Muller tube cannot be used to generate spectral information about the incident radiation.
In practice the termination of the avalanche is improved by the use of "quenching" techniques. Pressure of the fill gas is important in the generation of avalanches. Too low a pressure and the efficiency of interaction with incident radiation is reduced. Too high a pressure, the “mean free path” for collisions between accelerated electrons and the fill gas is too small, the electrons cannot gather enough energy between each collision to cause ionisation of the gas; the energy gained by electrons is proportional to the ratio “e/p”, where “e” is the electric field strength at that point in the gas, “p” is the gas pressure. Broadly, there are two main types of Geiger tube construction. For alpha particles, low energy beta particles, low energy X-rays, the usual form is a cylindrical end-window tube; this type has a window at one end covered in a thin material through which low-penetrating radiation can pass. Mica is a used material due to its low mass per unit area; the other end houses the electrical connection to the anode.
The pancake tube is a variant of the end window tube, but, designed for use for beta and gamma contamination monitoring. It has the same sens
The George Medal, instituted on 24 September 1940 by King George VI, is a decoration of the United Kingdom and Commonwealth, awarded for gallantry "not in the face of the enemy" where the services were not so outstanding as to merit the George Cross. In 1940, during the height of the Blitz, there was a strong desire to reward the many acts of civilian courage; the existing awards open to civilians were not judged suitable to meet the new situation, therefore it was decided that the George Cross and the GM would be instituted to recognise both civilian gallantry in the face of enemy bombing and brave deeds more generally. Announcing the new awards, the King said: In order that they should be worthily and promptly recognised, I have decided to create, at once, a new mark of honour for men and women in all walks of civilian life. I propose to give my name to this new distinction, which will consist of the George Cross, which will rank next to the Victoria Cross, the George Medal for wider distribution.
The Warrant for the GM, dated 24 January 1941, was published in The London Gazette on 31 January 1941. The medal is granted in recognition of "acts of great bravery"; the original warrant for the George Medal did not explicitly permit it to be awarded posthumously. This was changed in December 1977 to allow posthumous awards, several of which have been subsequently made; the medal is a civilian award, but it may be awarded to military personnel for gallant conduct, not in the face of the enemy. As the Warrant states: The Medal is intended for civilians and award in Our military services is to be confined to actions for which purely military Honours are not granted. Recipients are entitled to the post-nominal letters GM. Bars are awarded to the GM in recognition of the performance of further acts of bravery meriting the award. In undress uniform or on occasions when the medal ribbon alone is worn, a silver rosette is worn on the ribbon to indicate each bar; the details of all awards to British and Commonwealth recipients are published in The London Gazette.
2,122 medals have been awarded since its inception in 1940, with 27 second award bars. The GM is a circular silver medal 36 mm in diameter, with the ribbon suspended from a ring, it has the following design. The obverse depicts the crowned effigy of the reigning monarch. To date, there have been four types: The reverse shows St George on horseback slaying the dragon on the coast of England, with the legend THE GEORGE MEDAL around the top edge of the medal; the ribbon is crimson with five narrow blue stripes. The blue colour is taken from the George Cross ribbon. Worn on the left chest by men, women not in uniform wear the medal on the left shoulder, with the ribbon fashioned into a bow; the name of the recipient is engraved on the rim of the medal, although some Army awards have impressed naming. The first recipients, listed in the London Gazette of 30 September 1940, were Chief Officer Ernest Herbert Harmer and Second Officer Cyril William Arthur Brown of the Dover Fire Brigade, Section Officer Alexander Edmund Campbell of the Dover Auxiliary Fire Service, who on 29 July had volunteered to return to a ship loaded with explosives in Dover Harbour to fight fires aboard while an air raid was in progress.
Seven other people were awarded the medal, including the first women. The first recipient chronologically was Coxswain Robert Cross, commander of the RNLI lifeboat City of Bradford, based at Spurn Point, whose award was gazetted on 7 February 1941, it was awarded for an incident on 2 February 1940 when Cross took the lifeboat out in gale force winds and rough seas to rescue the crew of a steam trawler. The youngest recipient was Charity Anne Bick, who lied about her age to join the ARP service at 14 years old, who delivered several messages by bicycle during a heavy air raid in West Bromwich in late 1940; the first person to receive a second award was George Samuel Sewell, an engineer working for Shell-Mex and B. P. Ltd. based at the oil terminal at Salt End, near Hull, for his actions during an air raid. Having been one of the first recipients in September 1940, his bar to the George Medal was gazetted on 4 July 1941.2015 was the 75th anniversary of the creation of the award and was marked with a ceremony in London.
Orders and decorations of the Commonwealth realms Abbott, P. E.. A.. British Gallantry Awards. London: Nimrod Dix and Co. ISBN 9780902633742. Dorling, H. Taprell and Medals, A. H. Baldwin & Son Duckers, Peter. British Gallantry Awards 1855–2000. Princes Risborough, Buckinghamshire: Shire Publications. ISBN 9780747805168. Henderson, P.. Dragons Can be Defeated: A Complete Record of the George Medal's Progress, 1940-83. London: Spink & Son Ltd. ISBN 978-0907605140. Mussell, John W.. The Medal Yearbook 2015. Devon, UK: Token Publishing. ISBN 9781908828248. McDermott, P.. Acts of Courage, Register of The George Medal 1940-2015. Bromsgrove: Worcestershire Medal Service Ltd. ISBN 9780995553101. New Zealand Defence Force – Medal information page Search recommendations for the George Medal on The UK National Archives' website British Military & Criminal History in the period 1900 to 1999 – George Medal
The Gambia the Republic of The Gambia, is a country in West Africa, entirely surrounded by Senegal with the exception of its western coastline along the Atlantic Ocean. It is the smallest country within mainland Africa; the Gambia is situated on both sides of the lower reaches of the Gambia River, the nation's namesake, which flows through the centre of The Gambia and empties into the Atlantic Ocean. It has an area of 10,689 square kilometres with a population of 1,857,181 as of the April 2013 census. Banjul is the Gambian capital and the largest cities are Serekunda and Brikama; the Gambia shares historical roots with many other West African nations in the slave trade, the key factor in the placing and keeping of a colony on the Gambia River, first by the Portuguese, during which era it was known as A Gâmbia. On 25 May 1765, The Gambia was made a part of the British Empire when the government formally assumed control, establishing the Province of Senegambia. In 1965, The Gambia gained independence under the leadership of Dawda Jawara, who ruled until Yahya Jammeh seized power in a bloodless 1994 coup.
Adama Barrow became The Gambia's third president in January 2017, after defeating Jammeh in December 2016 elections. Jammeh accepted the results refused to accept them, which triggered a constitutional crisis and military intervention by the Economic Community of West African States, resulting in his exile; the Gambia's economy is dominated by farming and tourism. In 2015, 48.6% of the population lived in poverty. In rural areas, poverty is more widespread, at 70%; the name "Gambia" is derived from the Mandinka term Kambra/Kambaa. According to the CIA World Factbook, the US Department of State, the Times Comprehensive Atlas of the World and the Permanent Committee on Geographical Names for British Official Use, The Gambia is one of few countries whose self-standing short name for official use should begin with the word "The". Upon independence in 1965, the country used the name The Gambia. Following the proclamation of a republic in 1970, the long-form name of the country became Republic of The Gambia.
The administration of Yahya Jammeh changed the long-form name to Islamic Republic of The Gambia in December 2015. On 29 January 2017 President Adama Barrow changed the name back to Republic of The Gambia. Arab traders provided the first written accounts of the Gambia area in the ninth and tenth centuries. During the tenth century, Muslim merchants and scholars established communities in several West African commercial centres. Both groups established trans-Saharan trade routes, leading to a large export trade of local people as slaves gold and ivory, as well as imports of manufactured goods. By the 11th or 12th century, the rulers of kingdoms such as Takrur, a monarchy centred on the Senegal River just to the north, ancient Ghana and Gao had converted to Islam and had appointed to their courts Muslims who were literate in the Arabic language. At the beginning of the 14th century, most of what is today called The Gambia was part of the Mali Empire; the Portuguese reached this area by sea in the mid-15th century, began to dominate overseas trade.
In 1588, the claimant to the Portuguese throne, António, Prior of Crato, sold exclusive trade rights on the Gambia River to English merchants. Letters patent from Queen Elizabeth I confirmed the grant. In 1618, King James I of England granted a charter to an English company for trade with the Gambia and the Gold Coast. Between 1651 and 1661, some parts of the Gambia were under the rule of the Duchy of Courland and Semigallia belonging to Polish-Lithuanian Commonwealth—modern-day Latvia—and were bought by Prince Jacob Kettler. During the late 17th century and throughout the 18th century, the British Empire and the French Empire struggled continually for political and commercial supremacy in the regions of the Senegal River and the Gambia River; the British Empire occupied the Gambia when an expedition led by Augustus Keppel landed there following the Capture of Senegal in 1758. The 1783 First Treaty of Versailles gave Great Britain possession of the Gambia River, but the French retained a tiny enclave at Albreda on the river's north bank.
This was ceded to the United Kingdom in 1856. As many as three million people may have been taken as slaves from this general region during the three centuries that the transatlantic slave trade operated, it is not known how many people were taken as slaves by intertribal wars or Muslim traders before the transatlantic slave trade began. Most of those taken were sold by other Africans to Europeans: some were prisoners of intertribal wars. Traders sent people to Europe to work as servants until the market for labour expanded in the West Indies and North America in the 18th century. In 1807, the United Kingdom abolished the slave trade throughout its empire, it tried, unsuccessfully, to end the slave trade in the Gambia. Slave ships intercepted by the Royal Navy's West Africa Squadron in the Atlantic were returned to the Gambia, with people, slaves released on MacCarthy Island far up the Gambia River where they were expected to establish new lives; the British established the military post of Bathurst in 1816.
In the ensuing years, Banjul was at times under the jurisdiction of the British Governor-General in Sierra Leone. In 1888, The Gambia became a separate colony. An agreement with the French Republic in 1889 established the present boundaries; the Gambia became a British Crown colony called Briti
General Motors Company referred to as General Motors, is an American multinational corporation headquartered in Detroit that designs, manufactures and distributes vehicles and vehicle parts, sells financial services, with global headquarters in Detroit's Renaissance Center. It was founded by William C. Durant on September 16, 1908 as a holding company; the company is the largest American automobile manufacturer, one of the world's largest. As of 2018, General Motors is ranked #10 on the Fortune 500 rankings of the largest United States corporations by total revenue. General Motors manufactures vehicles in 37 countries, it owns or holds controlling interest in foreign brands such as Holden, Wuling and Jiefang. Annual worldwide sales volume reached a milestone of 10 million vehicles in 2016. In addition to its twelve brands, General Motors holds a 20% stake in IMM, a 77% stake in GM Korea, it has a number of joint-ventures, including Shanghai GM, SAIC-GM-Wuling and FAW-GM in China, GM-AvtoVAZ in Russia, GM Uzbekistan, General Motors India, General Motors Egypt, Isuzu Truck South Africa.
General Motors does business in more than 140 countries. General Motors is divided into four business segments: GM North America, GM International Operations, GM Cruze, GM Financial; the company operates a mobility division called Maven, which operates car-sharing services in the United States, is studying alternatives to individual vehicle ownership. GM Defense is General Motors' military defense division, catering to the needs of the military for advanced technology and propulsion systems for military vehicles. General Motors led global vehicle sales for 77 consecutive years from 1931 through 2007, longer than any other automaker, in 2012 was among the world's largest automakers by vehicle unit sales. General Motors acts in most countries outside the U. S. via wholly owned subsidiaries, but operates in China through 10 joint ventures. GM's OnStar subsidiary provides vehicle safety and information services. In 2009, General Motors shed several brands, closing Saturn and Hummer, emerged from a government-backed Chapter 11 reorganization.
In 2010, the reorganized GM made an initial public offering, one of the world's top five largest IPOs to date, returned to profitability that year. General Motors Company was formed with an escrow account set up by R S McLaughlin for 15 years of Buick Motors in 1907 on September 16, 1908, in Flint, Michigan, as a holding company controlled by William C. Durant, owner of Buick. At the beginning of the 20th century, there were fewer than 8,000 automobiles in the U. S. and Durant had become a leading manufacturer of horse-drawn vehicles in Flint helped by his purchase of the Carriage Gear patent from the McLaughlin family in Canada, in the 1880s and 1890s, before making his foray into the automotive industry in 1904 by purchasing the fledgling Buick Motor Company. GM's co-founder was Charles Stewart Mott, whose carriage company was merged into Buick prior to GM's creation in 1918. Over the years, Mott became the largest single stockholder in The USA, spent his life with his Mott Foundation, which has benefited the city of Flint, his adopted home.
GM acquired Oldsmobile that year. In 1909, Durant brought in Cadillac, Elmore and several others. In 1909, GM acquired the Reliance Motor Truck Company of Owosso and the Rapid Motor Vehicle Company of Pontiac, the predecessors of GMC Truck. Durant, along with R. S. McLaughlin, lost control of GM in 1910 to a bankers who held the Escrow account' trust, because of the large amount of debt taken on in its acquisitions, coupled with a collapse in new vehicle sales; the next year, Durant started the Chevrolet Motor Car Company in the U. S. and in Canada in 1915, through this, he and McLaughlin in Canada secretly purchased a controlling interest in GM. Durant regained control of the company after one of the most dramatic proxy wars in U. S. business history. Durant reorganized General Motors Holding Company into General Motors Company in 1916, merging Chevrolet with GM and allying General Motors of Canada Limited in 1918 after McLaughlin Traded his Outstanding Stocks for GM stocks to allow the Corporation in the USA.
Shortly thereafter, he again lost control, this time for good, after the new vehicle market collapsed. Alfred P. Sloan was picked to take charge of the corporation, led it to its post-war global dominance when the seven manufacturing facilities operated by Chevrolet before Chevrolet acquired the company began to contribute to GM operations; these facilities were added to the individual factories that were exclusive to Cadillac, Oldsmobile and other companies acquired by the corporation. This unprecedented growth of GM would last into the early 1980s, when it employed 349,000 workers and operated 150 assembly plants in the USA. On July 10, 2009, General Motors emerged from government backed Chapter 11 reorganization after an initial filing on June 8, 2009. Through the Troubled Asset Relief Program the US Treasury invested $49.5 billion in General Motors and recovered $39 billion when it sold its shares on December 9, 2013 resulting in a loss of $10.3 billion. The Treasury invested an additional $17.2 billion into GM's former financing company, GMAC.
The shares in Ally were sold on December 2014 for $19.6 billion netting $2.4 billion. A study by the Center for Automotive Research found that the GM bailout saved 1.2 million jobs and preserved $34.9 billion in tax revenue. In 2009 General Motors of Canada Limited was not part of the General Motors Chapter 11 Bankruptcy, the company shed several brands
Orders of magnitude (length)
The following are examples of orders of magnitude for different lengths. To help compare different orders of magnitude, the following list describes various lengths between 1.6 × 10 − 35 metres and 10 10 10 122 metres. To help compare different orders of magnitude, this section lists lengths shorter than 10−23 m. 1.6 × 10−11 yoctometres – the Planck length. 1 ym – 1 yoctometre, the smallest named subdivision of the metre in the SI base unit of length, one septillionth of a metre 1 ym – length of a neutrino. 2 ym – the effective cross-section radius of 1 MeV neutrinos as measured by Clyde Cowan and Frederick Reines To help compare different orders of magnitude, this section lists lengths between 10−23 metres and 10−22 metres. To help compare different orders of magnitude, this section lists lengths between 10−22 m and 10−21 m. 100 ym – length of a top quark, one of the smallest known quarks To help compare different orders of magnitude, this section lists lengths between 10−21 m and 10−20 m. 2 zm – length of a preon, hypothetical particles proposed as subcomponents of quarks and leptons.
2 zm – radius of effective cross section for a 20 GeV neutrino scattering off a nucleon 7 zm – radius of effective cross section for a 250 GeV neutrino scattering off a nucleon To help compare different orders of magnitude, this section lists lengths between 10−20 m and 10−19 m. 15 zm – length of a high energy neutrino 30 zm – length of a bottom quark To help compare different orders of magnitude, this section lists lengths between 10−19 m and 10−18 m. 177 zm – de Broglie wavelength of protons at the Large Hadron Collider To help compare different orders of magnitude, this section lists lengths between 10−18 m and 10−17 m. 1 am – sensitivity of the LIGO detector for gravitational waves 1 am – upper limit for the size of quarks and electrons 1 am – upper bound of the typical size range for "fundamental strings" 1 am – length of an electron 1 am – length of an up quark 1 am – length of a down quark To help compare different orders of magnitude, this section lists lengths between 10−17 m and 10−16 m. 10 am – range of the weak force To help compare different orders of magnitude, this section lists lengths between 10−16 m and 10−15 m. 100 am – all lengths shorter than this distance are not confirmed in terms of size 850 am – approximate proton radius The femtometre is a unit of length in the metric system, equal to 10−15 metres.
In particle physics, this unit is more called a fermi with abbreviation "fm". To help compare different orders of magnitude, this section lists lengths between 10−15 metres and 10−14 metres. 1 fm – length of a neutron 1.5 fm – diameter of the scattering cross section of an 11 MeV proton with a target proton 1.75 fm – the effective charge diameter of a proton 2.81794 fm – classical electron radius 7 fm – the radius of the effective scattering cross section for a gold nucleus scattering a 6 MeV alpha particle over 140 degrees To help compare different orders of magnitude, this section lists lengths between 10−14 m and 10−13 m. 1.75 to 15 fm – Diameter range of the atomic nucleus To help compare different orders of magnitude, this section lists lengths between 10−13 m and 10−12 m. 570 fm – typical distance from the atomic nucleus of the two innermost electrons in the uranium atom, the heaviest naturally-occurring atom To help compare different orders of magnitude this section lists lengths between 10−12 and 10−11 m. 1 pm – distance between atomic nuclei in a white dwarf 2.4 pm – The Compton wavelength of the electron 5 pm – shorter X-ray wavelengths To help compare different orders of magnitude this section lists lengths between 10−11 and 10−10 m. 25 pm – approximate radius of a helium atom, the smallest neutral atom 50 pm – radius of a hydrogen atom 50 pm – bohr radius: approximate radius of a hydrogen atom ~50 pm – best resolution of a high-resolution transmission electron microscope 60 pm – radius of a carbon atom 93 pm – length of a diatomic carbon molecule To help compare different orders of magnitude this section lists lengths between 10−10 and 10−9 m. 100 pm – 1 ångström 100 pm – covalent radius of sulfur atom 120 pm – van der Waals radius of a neutral hydrogen atom 120 pm – radius of a gold atom 126 pm – covalent radius of ruthenium atom 135 pm – covalent radius of technetium atom 150 pm – Length of a typical covalent bond 153 pm – covalent radius of silver atom 155 pm – covalent radius of zirconium atom 175 pm – covalent radius of thulium atom 200 pm – highest resolution of a typical electron microscope 225 pm – covalent radius of caesium atom 280 pm – Average size of the water molecule 298 pm – radius of a caesium atom, calculated to be the largest atomic radius 340 pm – thickness of single layer graphene 356.68 pm – width of diamond unit cell 403 pm – width of lithium fluoride unit cell 500 pm – Width of protein α helix 543 pm – silicon lattice spacing 560 pm – width of sodium chloride unit cell 700 pm – width of glucose molecule 780 pm – mean width of quartz unit cell 820 pm – mean width of ice unit cell 900 pm – mean width of coesite unit cell To help compare different orders