Electricity Definition and 999 Threads

Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwell's equations. Various common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others.
The presence of an electric charge, which can be either positive or negative, produces an electric field. The movement of electric charges is an electric current and produces a magnetic field.
When a charge is placed in a location with a non-zero electric field, a force will act on it. The magnitude of this force is given by Coulomb's law. If the charge moves, the electric field would be doing work on the electric charge. Thus we can speak of electric potential at a certain point in space, which is equal to the work done by an external agent in carrying a unit of positive charge from an arbitrarily chosen reference point to that point without any acceleration and is typically measured in volts.
Electricity is at the heart of many modern technologies, being used for:

Electric power where electric current is used to energise equipment;
Electronics which deals with electrical circuits that involve active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies.Electrical phenomena have been studied since antiquity, though progress in theoretical understanding remained slow until the seventeenth and eighteenth centuries. The theory of electromagnetism was developed in the 19th century, and by the end of that century electricity was being put to industrial and residential use by electrical engineers. The rapid expansion in electrical technology at this time transformed industry and society, becoming a driving force for the Second Industrial Revolution. Electricity's extraordinary versatility means it can be put to an almost limitless set of applications which include transport, heating, lighting, communications, and computation. Electrical power is now the backbone of modern industrial society.

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  1. Ackbach

    MHB Solve Sign Issues in Elec. Potential, Energy, Force, Field, Work

    I had some trouble reconciling signs while attempting to teach electricity to my students here. The topic is electric potential, potential energy, electric force, electric field, and work. After much thought - several hours - I have finally come up with a presentation that solves the issues...
  2. E

    Electricity with conservation of energy involved.

    A tiny sphere of mass 7.70 µg and charge −2.80 nC is initially at a distance of 1.74 µm from a fixed charge of +9.25 nC. (a) If the 7.70-µg sphere is released from rest, find its kinetic energy when it is 0.500 µm from the fixed charge. (b) If the 7.70-µg sphere is released from rest, find...
  3. R

    Electric Shock Risk From AC Generator: Can You Touch 1 Terminal?

    Can one get electric shock by touching only one terminal of AC generator ?
  4. M

    The future methods of generating electricity?

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  5. K

    Understanding the Role of Grounding in AC Single Phase Systems

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  6. I

    Good study guide for Electricity and Magnetism?

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  7. C

    Electricity and magnetism ( word problems )

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  8. M

    Electricity and Electric Field Questions

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  9. M

    The speed of electricity and the loses

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  10. bcrowell

    Classical Electricity and Magnetism by Edward Purcell

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  11. B

    Is there a material that can emit gamma radiation when heated by electricity?

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  12. N

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  13. H

    Difference between electricity and electromagnetic waves

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  14. R

    Electricity & Magnetism + Quantum Mechanics?

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  15. D

    Electricity and magnetism confusion

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  16. B

    Creating static electricity from an electrical current

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  17. H

    How do electricity and superconductors work?

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  18. R

    Eric Giler: Wireless Electricity Demo

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  19. M

    Calculating the Voltage for a Proton Floating Between Two Boards

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  20. denjay

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  21. S

    How can Coulomb's Law be used to find the force between a charge and a surface?

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  22. W

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  23. K

    Generate electricity by gravitational force?

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  24. V

    Electricity: How Current Works

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  25. G

    Layden jar questions? And some static electricity questions.?

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  26. P

    How Does an Electric Field Affect Electron Energy in a Battery?

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  27. S

    Transfer of electricity wihout loss safely.

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  28. A

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  29. Newtons Apple

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  30. L

    Medical Did David Blaine's Electricity Stunt Cause Permanent Heart Damage?

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  31. nukeman

    Electricity & Flies: Exploring the Safety of Charged Fluids

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  32. C

    Help with this problem about electricity

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  33. Y

    Is Electricity Generated when a Magnet Falls Through a Copper Pipe?

    The title is pretty self-explanatory. I know the speed of the falling magnet is much slower in a copper pipe, but since the magnetic field moves, is there still some electricity generated in the process, even though the speed isn't great? Thanks!
  34. R

    Creating electricity through pressure difference

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  35. G

    Any type of material that expands with electricity?

    Is there any type of liquid or solid, or any material that will expand with the addition of electricity, or vice versa?
  36. P

    How does electricity really flow?

    I'm in grade 11 and we still haven't looked into how electricity really flows. Right now all we're told is that the electrons move from atom to atom, the quantity of electrons dictates the current (in coulombs, however you spell that), and the amount of energy in each electron is the voltage...
  37. P

    Electricity and Kirchhoff's Laws

    Homework Statement Given two batteries in parallel, one of 10V and 5Ω, and the other of 5V and 2Ω, which is attached to a 3Ω resistor, find the current that flows from the 10V battery, if the system described above is connected to a 20 resistor. Homework Equations Kirchhoff's two laws...
  38. A

    Electricity production from a magnetic field.

    Is it possible to recharge a device, say of 15-2by converting the magnetic field is produced by electricity flow through any random wire anywhere? This is for an important exhibition and so i request an in depth answer which helps me figure out the hows and whats... thanx
  39. H

    What is the deal with kinetic and potential energy, electricity and magnetism

    Hello, Firstly i am new here ( not offering an excuse) and an on and off lurker to this awesome forum. I am trying my best to fit into the established rules ,sorry if i broke any inadvertently. If kinetic and potential energy represent the same things why are there entities representing the...
  40. H

    Magnets generating electricity, non-fixed placements.

    I'm new to the forum so I'm sorry if this question is posted in the wrong place. I have been doing some research on magnetic motors and they seem possible, but I am not talking about the fixed magnet motors where all of the magnets stay in the same position. I found this video where there is a...
  41. N

    Water analogy as electricity explanation

    Thinking of a restrictive pipe as an analogy of a resistor, which converts electrical energy to heat, would a pipe demonstrate a rise in temperature related to the loss of energy in the water, . (theoretically - and assuming conditions which did not have other influences - so water at ambient...
  42. S

    Need explanation on how electrons and electricity work

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  43. W

    How electricity moves through wires

    Can electrical currents in a wire affect each other? Imagine racecars and how they affect each other in a race for this. Reply in simple english please.
  44. S

    Fan Speed and Electricity Consumed

    Does a ceiling fan consume more electicity at higher speeds or is the same at all speeds?
  45. G

    Electricity Question for Unit 2 Edexcel

    Homework Statement If lightning strikes a tree such that there is the same current through it as there was through the lightning conductor, then a much larger potential difference exists between top and bottom of the tree. Explain why this is so. The Attempt at a Solution Is this...
  46. B

    Textbook for junior level electricity and magnetism

    Since the instructor of my course doesn't use a textbook and just teaches based off his notes, what would be a good text to supplement my learning (when asked what he recomends, he just said find something in the library). Does electrodynamics = electricty and magnetism? I've heard this one is...
  47. M

    How do you calculate cost per unit of electricity?

    How do you calculate cost per unit of electricity over a certain time that a generator produces?
  48. J

    Electricity & Magnetism Honors Project Ideas?

    I am going into my fall semester of E&M and am trying to decide upon a topic to write about for an honors project. I have not taken an E&M course yet so it is difficult for me to really find which topics are too advanced scientifically or mathematically at this point. So far I have taken a...
  49. R

    Science-Fiction: What could impede the use of electricity on half of Mars?

    Hello. I’m a new addition to the board, and if I’ve posted in the wrong place or this is otherwise unwelcome, please PM me and let me know. I’m a writer and I’m working on a science-fiction novel set on Mars in the distant future. I can gather most of the information on the planet, the...
  50. S

    When Electricity Takes the Shortest Path, is that Due to Quantum Mechanics?

    Hello all! I was recently watching a documentary which delved into the theory (is it a theory?) that quantum particles can be in two places at once; indeed, millions of places at once. I've heard this all before, but the one thing that I picked up on this time was that when a particle is...
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