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  1. 55.263 494 06. e2 ⋅ eV −1 ⋅ μm −1. Vacuum permittivity, commonly denoted ε0 (pronounced "epsilon nought" or "epsilon zero"), is the value of the absolute dielectric permittivity of classical vacuum. It may also be referred to as the permittivity of free space, the electric constant, or the distributed capacitance of the vacuum.

  2. The three candidate cities were Tokyo, Istanbul, and Madrid.The applicant cities of Baku and Doha were not promoted to candidate status. A bid from Rome was withdrawn. Host city selection The International Olympic Committee (IOC) voted to select the host city of the 2020 Summer Olympics on 7 September 2013, at the 125th IOC Session in Buenos Aires, Argentina, using an exhaustive ballot system.

  3. The 2020 Atlantic hurricane season was the most active Atlantic hurricane season on record, in terms of number of systems. It featured a total of 31 tropical or subtropical cyclones, with all but one cyclone becoming a named storm. Of the 30 named storms, 14 developed into hurricanes, and a record-tying seven further intensified into major ...

  4. Wikipedia is written by volunteer editors and hosted by the Wikimedia Foundation, a non-profit organization that also hosts a range of other volunteer projects : Commons. Free media repository. MediaWiki. Wiki software development. Meta-Wiki. Wikimedia project coordination. Wikibooks. Free textbooks and manuals.

  5. en.wikipedia.org › wiki › IP_CodeIP code - Wikipedia

    IP65 touchscreen display IP65 LED lamp The IP code or ingress protection code indicates how well a device is protected against water and dust. It is defined by the International Electrotechnical Commission (IEC) under the international standard IEC 60529 which classifies and provides a guideline to the degree of protection provided by mechanical casings and electrical enclosures against ...

  6. The Chernobyl disaster [a] began on 26 April 1986 with the explosion of the No. 4 reactor of the Chernobyl Nuclear Power Plant near the city of Pripyat in the north of the Ukrainian SSR, close to the border with the Byelorussian SSR, in the Soviet Union. [1] It is one of only two nuclear energy accidents rated at seven—the maximum severity ...

  7. en.wikipedia.org › wiki › SunSun - Wikipedia

    Sun. The Sun is the star at the center of the Solar System. It is a massive, nearly perfect sphere of hot plasma, [18] [19] heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light and infrared radiation with 10% at ultraviolet energies.