كولوم

For other uses, see كولوم (توضيح).
coulomb
Charles de Coulomb.png
Charles-Augustin de Coulomb
معلومات عامة
نظام الوحداتSI
وحدة قياسelectric charge
الرمزC 
مسمى على اسمCharles-Augustin de Coulomb
التحويلات
1 C في ...... يساوي ...
   SI base units   A⋅s
   CGS units   ≘ 2997924580 statC
   Atomic units   6.241509×1018 e[1]

الكولوم هو كمية الشحنة الكهربائية الذي يحمله تيار مقداره أمبير واحد في ثانية واحدة. سمي الكولوم نسبة إلى الفيزيائي الفرنسي شارل أوغستان دي كولوم.

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التعريف

كولوم=أمبير*ثانية

2019 redefinition of the ampere and other SI base units fixed the numerical value of the elementary charge when expressed in coulombs, and therefore fixed the value of the coulomb when expressed as a multiple of the fundamental charge (the numerical values of those quantities are the multiplicative inverses of each other). The ampere is defined by taking the fixed numerical value of the elementary charge e to be 1.602176634×10−19 coulombs.[2] The ampere was previously defined in terms of two wires of infinite extent.

Thus, one coulomb is the charge of approximately 6241509074460762607.776 elementary charges, where the number is the reciprocal of 1.602176565(35)×10−19 C.[3] It is impossible to realize exactly 1 C of charge, since the number of elementary charges is not an integer.

By 1878, the British Association for the Advancement of Science had defined the volt, ohm, and farad, but not the coulomb.[4] In 1881, the International Electrical Congress, now the International Electrotechnical Commission (IEC), approved the volt as the unit for electromotive force, the ampere as the unit for electric current, and the coulomb as the unit of electric charge.[5] At that time, the volt was defined as the potential difference [i.e., what is nowadays called the "voltage (difference)"] across a conductor when a current of one ampere dissipates one watt of power. The coulomb (later "absolute coulomb" or "abcoulomb" for disambiguation) was part of the EMU system of units. The "international coulomb" based on laboratory specifications for its measurement was introduced by the IEC in 1908. The entire set of "reproducible units" was abandoned in 1948 and the "international coulomb" became the modern coulomb.[6]


SI prefixes

المقالة الرئيسية: Orders of magnitude (charge)

Like other SI units, the coulomb can be modified by adding a prefix that multiplies it by a power of 10.

مضاعفات SI لوحدة coulomb (C)
الأقسام المضاعفات
القيمة الرمز الاسم القيمة الرمز الاسم
10–1 C دC دسيcoulomb 101 C داC دكاcoulomb
10–2 C سC سنتيcoulomb 102 C هـC هكتوcoulomb
10–3 C مC مليcoulomb 103 C كC كيلوcoulomb
10–6 C µC ميكروcoulomb 106 C مC مگاcoulomb
10–9 C نC نانوcoulomb 109 C گC گيگاcoulomb
10–12 C پيC پيكوcoulomb 1012 C تC تـِراcoulomb
10–15 C فC فمتوcoulomb 1015 C پC پتاcoulomb
10–18 C أC أتـّوcoulomb 1018 C إC إكساcoulomb
10–21 C زC زپتوcoulomb 1021 C زC زتـّاcoulomb
10–24 C يC يوكتوcoulomb 1024 C يC يوتـّاcoulomb
Common multiples are in bold face.


تحويلات

  • The magnitude of the electrical charge of one mole of elementary charges (approximately 6.022×1023, the Avogadro number) is known as a faraday unit of charge (closely related to the Faraday constant). One faraday equals 96485.3365(21) coulombs.[7] In terms of the Avogadro constant (NA), one coulomb is equal to approximately 1.036×10−5 mol × NA elementary charges.
  • A capacitor of one farad can hold one coulomb at a drop of one volt.
  • One ampere hour equals 3600 C, hence 1 mA⋅h = 3.6 C.
  • One statcoulomb (statC), the obsolete CGS electrostatic unit of charge (esu), is approximately 3.3356×10-10 C or about one-third of a nanocoulomb.

في مصطلحات كل يوم

  • The charges in static electricity from rubbing materials together are typically a few microcoulombs.[8]
  • The amount of charge that travels through a lightning bolt is typically around 15 C, although for large bolts this can be up to 350 C.[9]
  • The amount of charge that travels through a typical alkaline AA battery from being fully charged to discharged is about 5 kC = 5000 C ≈ 1400 mA⋅h.[10]
  • A typical smartphone battery can hold 10,800 C ≈ 3000 mA⋅h.

انظر أيضاً

ملاحظات ومراجع

  1. ^ 6.241509074...×1018 is the reciprocal of the 2018 CODATA recommended value of the elementary charge, 1.602176634×10−19 C.
  2. ^ "SI brochure (2019)" (PDF). SI Brochure. BIPM. p. 132. Retrieved May 23, 2019.
  3. ^ "CODATA Value: elementary charge". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2011. Retrieved 2011-06-23. {{cite web}}: Cite has empty unknown parameter: |month= (help); External link in |work= (help)
  4. ^ W. Thomson, et al. (1873) "First report of the Committee for the Selection and Nomenclature of Dynamical and Electrical Units," Report of the 43rd Meeting of the British Association for the Advancement of Science (Bradford, September 1873), pp. 222–225. From p. 223: "The "ohm", as represented by the original standard coil, is approximately 109 C.G.S. units of resistance; the "volt" is approximately 108 C.G.S. units of electromotive force; and the "farad" is approximately 1/109 of the C.G.S. unit of capacity."
  5. ^ (Anon.) (September 24, 1881) "The Electrical Congress," The Electrician, 7.
  6. ^ Donald Fenna, A Dictionary of Weights, Measures, and Units, OUP (2002), 51f.
  7. ^ "CODATA Value: Faraday constant". The NIST Reference on Constants, Units, and Uncertainty. US National Institute of Standards and Technology. June 2011. Retrieved 2011-06-23. {{cite web}}: Cite has empty unknown parameter: |month= (help); External link in |work= (help)
  8. ^ Martin Karl W. Pohl. "Physics: Principles with Applications" (PDF). DESY. Archived from the original (PDF) on 2011-07-18.
  9. ^ Hasbrouck, Richard. Mitigating Lightning Hazards Archived 2013-10-05 at the Wayback Machine, Science & Technology Review May 1996. Retrieved on 2009-04-26.
  10. ^ How to do everything with digital photography – David Huss, p. 23, في كتب گوگل, "The capacity range of an AA battery is typically from 1100–2200 mAh."
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