Elektricitet

Elektromagnetisme
Elektricitet  Magnetisme

Ved elektricitet forstås en række fysiske fænomener forbundet ved en tilstedeværelse og en strøm af elektrisk ladede partikler. Elektricitet har en bred vifte af effekter, f.eks. lyn, statisk elektricitet, elektromagnetisk induktion og elektrisk strøm. Desuden muliggør elektricitet dannelse og opfangning af elektromagnetisk stråling såsom radiobølger.

Effekter

Såkaldt statisk elektricitet er ikke en elektronstrøm. Det skyldes et over- eller underskud af elektroner i forhold til positive kernepartikler (protoner):

  • Når der er et overskud af elektroner, siges objektet at være "negativt ladet".
  • Når der er et underskud af elektroner, siges objektet at være "positivt ladet".
  • Når antallet af elektroner og antallet af protoner er ens, siges objektet at være "elektrisk neutralt".

Elektriske fænomener i naturen:

Elektricitet kan f.eks. genereres ved hjælp af følgende transducere:

Elektrokemiske:

Elektromekaniske:

Elektroakustiske:

Elektromagnetiske (baseret primært på den fotoelektriske effekt):

Elektrotermiske:

  • Peltier-element

Kilder/referencer

  1. ^ Jan 9, 2014, physicsworld.com: Burning soil fuels ball lightning Arkiveret 10. januar 2014 hos Wayback Machine Citat: "...In 2000 John Abrahamson and James Dinniss of the University of Canterbury in New Zealand suggested that ball lightning is caused by lightning striking silicon-rich soil..."
  2. ^ University of Florida. (2006, February 6). Scientists Trace Origin Of Shark's Electric Sense. ScienceDaily Arkiveret 23. september 2015 hos Wayback Machine Citat: "..."Sharks have a network of electrosensory cells that allows them to hunt by detecting electrical signals generated by prey," said Martin Cohn, a developmental biologist with the departments of zoology and anatomy and cell biology, and the UF Genetics Institute. "That doesn't mean they can only detect electric fish. They can sense electricity generated by a muscle twitch, even if it's the weak signal of a flounder buried under sand."..."
  3. ^ Washington University School of Medicine. (2008, May 7). Platypus Genome Explains Animal's Peculiar Features; Holds Clues To Evolution Of Mammals. ScienceDaily Arkiveret 11. juli 2015 hos Wayback Machine Citat: "...the platypus also sports a duck-like bill that holds a sophisticated electrosensory system used to forage for food underwater..."
  4. ^ University of Texas at Austin. (2009, September 29). Electric Fish Plug In To Communicate. ScienceDaily Arkiveret 6. september 2015 hos Wayback Machine Citat: "...They do so at night, while trying to avoid predators such as catfish that sense the electric fields..."
  5. ^ Washington University in St. Louis. (2015, August 4). Fish that have their own fish finders. ScienceDaily Arkiveret 5. august 2015 hos Wayback Machine Citat: "...The fish with nuanced signal discrimination can glean a stunning amount of information from electric signals, including the signaler's species, sex, age, relative dominance status, and possibly even individual identity. They can also detect emotional states, such as aggression, submission, courtship and active exploration. The fish with the simpler communication system were less studied and less well understood..."

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VFPt Solenoid correct2.svg
Forfatter/Opretter: Geek3, Licens: CC BY-SA 3.0
Diagram of a solenoid and its magnetic field lines. The shape of all lines was computed according to the laws of electrodynamics.