electronvoltn.

Brit.

/ᵻˈlɛktrɒnˌvəʊlt/, U.S.

/əˈlɛktrɑnˌvoʊlt/,

/iˈlɛktrɑnˌvoʊlt/

Origin: Formed within English, by compounding. Etymons: electron n.², volt n.

Etymology: < electron n.² + volt n.

Physics.

A unit of energy equal to the change in energy of an electron when it passes through a potential difference of one volt (approx. 1.602 × 10⁻¹⁹ joule); abbreviated eV.The masses of subatomic particles are usually expressed in terms of electronvolts. Through the equivalence of mass-energy, expressed by E = mc², where c is the speed of light, 1 eV/c² = 1.783 x 10⁻³⁶ kg; the factor 1/c² is conventionally omitted, so that a mass of 1.783 x 10⁻³⁶ kg is expressed as 1 eV. In practice the MeV (10⁶ eV) or Gev (10⁹ eV) is often a more convenient unit (cf. MeV n. at M n. Initialisms 4c, GeV n. at G n. Initialisms); e.g. the mass of the electron is 0.511 MeV.

ΚΠ

1925 Proc. Royal Soc. A. 109 559 Now one electron-volt = 1·59 .10⁻¹² ergs, and 4·18 .10⁻¹⁷ ergs = 1 gram-calorie.

1936 N. Feather Introd. Nucl. Physics ii. 41 α particles of 7.5 million electron volts energy from radium C′ are scattered by a thin layer of uranium.

1960 Amer. Jrnl. Internat. Law 54 609 The construction of..a cyclotron of 25 million electronvolt power.

1984 E. P. DeGarmo et al. Materials & Processes in Manuf. (ed. 6) xxxvii. 925 Because of the energy of these atoms, usually between 15 and 50 electron volts, their adherence to the substrate is considerably better.

1991 New Scientist 6 Apr. 22/1 The telescope..will detect X-rays with energies ranging from 100 to 10,000 electronvolts (0.1 to 10 keV).

1996 S. N. Kaplan & H. Maccabee in S. A. Berger et al. Introd. Bioengin. xiii. 479/1 It was recognized that photon beam energies in excess of 1 million electronvolts (megavoltage) were necessary.

2002 F. Close et al. Particle Odyssey vi. 81 The tunnel contains 1000 electromagnets, designed to steer protons in a circular course until they reach energies as high as 1 tera electronvolts (TeV)—a million million electronvolts (eV).

This entry has been updated (OED Third Edition, June 2008; most recently modified version published online March 2022).

单词	electronvolt
释义	electronvoltn. Brit. /ᵻˈlɛktrɒnˌvəʊlt/, U.S. /əˈlɛktrɑnˌvoʊlt/, /iˈlɛktrɑnˌvoʊlt/ Origin: Formed within English, by compounding. Etymons: electron n.², volt n. Etymology: < electron n.² + volt n. Physics. A unit of energy equal to the change in energy of an electron when it passes through a potential difference of one volt (approx. 1.602 × 10⁻¹⁹ joule); abbreviated eV.The masses of subatomic particles are usually expressed in terms of electronvolts. Through the equivalence of mass-energy, expressed by E = mc², where c is the speed of light, 1 eV/c² = 1.783 x 10⁻³⁶ kg; the factor 1/c² is conventionally omitted, so that a mass of 1.783 x 10⁻³⁶ kg is expressed as 1 eV. In practice the MeV (10⁶ eV) or Gev (10⁹ eV) is often a more convenient unit (cf. MeV n. at M n. Initialisms 4c, GeV n. at G n. Initialisms); e.g. the mass of the electron is 0.511 MeV. ΚΠ 1925 Proc. Royal Soc. A. 109 559 Now one electron-volt = 1·59 .10⁻¹² ergs, and 4·18 .10⁻¹⁷ ergs = 1 gram-calorie. 1936 N. Feather Introd. Nucl. Physics ii. 41 α particles of 7.5 million electron volts energy from radium C′ are scattered by a thin layer of uranium. 1960 Amer. Jrnl. Internat. Law 54 609 The construction of..a cyclotron of 25 million electronvolt power. 1984 E. P. DeGarmo et al. Materials & Processes in Manuf. (ed. 6) xxxvii. 925 Because of the energy of these atoms, usually between 15 and 50 electron volts, their adherence to the substrate is considerably better. 1991 New Scientist 6 Apr. 22/1 The telescope..will detect X-rays with energies ranging from 100 to 10,000 electronvolts (0.1 to 10 keV). 1996 S. N. Kaplan & H. Maccabee in S. A. Berger et al. Introd. Bioengin. xiii. 479/1 It was recognized that photon beam energies in excess of 1 million electronvolts (megavoltage) were necessary. 2002 F. Close et al. Particle Odyssey vi. 81 The tunnel contains 1000 electromagnets, designed to steer protons in a circular course until they reach energies as high as 1 tera electronvolts (TeV)—a million million electronvolts (eV). This entry has been updated (OED Third Edition, June 2008; most recently modified version published online March 2022). < n.1925
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