What is Electricity: Definition and 999 Discussions

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. S

    Electricity and magnetism (magnitude of magnetic field)

    A 1000-turn toroidal solenoid has a central radius of 4.2 cm and is carrying a current of 1.7 A. What is the magnitude of the magnetic field inside the solenoid at the central radius? (μ0=4∏×10^-7 T ∙ m/A) r= 4.2cm= 0.042m B=(μ0)(I)/(2∏)(r) ⇔ (4∏×10^-7)(1.7)/(2∏)(0.042) ⇔ 1.43x10^-8 T? Or...
  2. S

    Electricity and magnetism (magnitude of current flowing)

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  3. K

    Can a DC Current Replicate the Glow of Hydrogen Peroxide in Glow Sticks?

    So from my understanding of glow sticks, the decomposition of hydrogen peroxide provides electrons that excites the fluorescent dye and gives off that classical glow-stick light source. My question is, could one put a DC current over the solution and still theoretically obtain the same...
  4. H

    Living Organism versus Electricity

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  5. M

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  6. K

    Is it possible to harness electricity from the ground of the earth?

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  7. E

    Why and how does static electricity destroy chips?

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  8. D

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  9. B

    Electricity, Direction of Charge Problem

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  10. C

    Studying Self Studying AP Physics C: Electricity and Magnetism

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  11. Lebombo

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  12. W

    Generating Electricity from an Aeroplane Flight

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  13. G

    Electricity - Resistance problem

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  14. B

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  15. Jadaav

    Static Electricity: What Causes Attraction?

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  16. TheTank

    Thinking about electricity and magnetism, and some relativity

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  17. T

    Static electricity and high voltage?

    I was just wondering how static electricity has a high voltage. Is it because of the difference of charge between the two objects e.g you and the ground? Or is it due to the electric field which surrounds an static charged object, so the electric field cause ions to build in the air allowing...
  18. A

    Air Flow in a 10m. pipe - generating electricity ?

    I have this idea about creating a 10 meter plastic/metal pipe that would go from a house roof to the ground and having a "U' shape close to the ground so that both holes are directed at the sky. Does anyone have a clue if the difference in atmospheirc pressure between both holes (10 meters...
  19. A

    Question about magnetism and electricity

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  20. BWV

    Is SEF Electric's Claim of Harnessing Electricity from the Air Just a Scam?

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  21. F

    Electricity: conceptual understanding help

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  22. G

    Generator speed to create electricity calculation?

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  23. A

    Obtaining Electricity from the Earth's Magnetic Field

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  24. gmax137

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  25. J

    Discovery of Electrons: A Stroke of Luck?

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  26. A

    Power loss between the electricity meter and the building

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  27. T

    Density of electrons in a metal (electricity)

    Homework Statement A metallic wire has a diameter of 4.12mm. When the current in the wire is 8.00 A, the drift velocity is 5.40 10^-5 m/s What is the density of free electrons in the metal? Express your answer numerically in m^-3 to two significant figures. Homework Equations I=nqv(drift)a...
  28. H

    Electricity- 2 objects of different power on same battery.

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  29. S

    Electricity and Magnetism: Forces on Conductors in Magnetic Fields

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  30. N

    Understanding Electricity Waste: TV vs. Reality

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  31. H

    If electricity is flow of electrons and also positive and negative

    if electricity is flow of electrons and also positive and negative charges attract then why electricity needs a conducting medium. electrons has mass and it should just travel through vaccum then why in vacuum electricity cann't travel please reply!
  32. V

    Static Electricity, Spheres question

    Homework Statement Suppose you have two isolated conducting spheres that are both neutral. You move 2mC of charge from one to the other. a. What is the charge now on each sphere? My solution: One sphere is positively charged with 2mC more protons, while the other is negatively charged with...
  33. D

    Current and Electricity Question

    i got it until ' R P(1) = 3 ohm ' but shouldn't the effective resistance of arm ADE be 6+3=9 and effect. resistance b/w A & E be (9*6) / 9+6 = 54/15 ?
  34. B

    Make electricity using your backyard stream

    I'm thinking about building a generator for my parents powered by a stream in their backyard. It would be a great way to learn about science. I'm trying to find the relevant equations so that I can estimate how much energy the stream produces. Right now I have this equation: ε = NBAω...
  35. C

    You can slow the group velocity of light. Can you slow electricity?

    There are various methods to slow and even stop visible light. Most of these methods appear to be slowing the group velocity of light, not the phase velocity. Can you slow the velocity of propagation of electricity? I have seen estimates that electricity, in a wire, propagates at 2/3 the...
  36. M

    Engineering ball sorting project, static electricity

    Hello all, I am an engineering student currently undertaking a project at univeristy. It involves the sorting of 4 different balls of which I have deduced how to sort 2 of them leaving just 2 types of balls to sort... The remaining two are of identical size, 10mm in radius, and are...
  37. H

    What is the relationship between AC electricity and transverse waves in copper?

    I was wondering if I may interprete AC current as a tranverse wave trough copper as medium. So this wave behaviour has a general wave-form written as: \zeta(x,t)=\zeta_{0}sin(kx-\omega.t) This is a solution to the partial differential equation: \frac{\partial^{2}\zeta}{\partial...
  38. C

    Power, electricity, multiple choice Q

    Homework Statement If you step up the voltage in a wire by a factor of 100, how is heat affected? A. No change B. Heat loss increases by a factor of 10000 C. Heat loss decreases by a factor of 10000 D. Not enough information to tell Answer: "C, heat loss decreases by a factor of 10000...
  39. T

    Salt water and tap water conducting electricity - help appreciated

    Salt water and tap water conducting electricity - help appreciated :) Hello, Thanks in advance for helping me with my question! I'm so excited to find this physics forum of such talented people. My question is, I know that salt water conducts electricity more than tap water due to the ions...
  40. H

    Coal-steam electricity generation

    Homework Statement A coal-fired steam power plant operates on the ideal Rankine cycle. Feedwater from the condenser at P1 = 10 kPa is pumped to the boiler at P2 = P3 = 20 MPa, where it is superheated and exits the boiler at T3 = 550 °C. The moisture content in the turbine is...
  41. D

    What's the part called that converts motor power into electricity?

    What's the part called that converts spinning, rotor, motor power into electricity? If I were to buy one what would I call it? Regards, David
  42. R

    Does RPM affect electricity generation?

    Let's say I have a magnet inside a coil of wire. If I spin the magnet for a 10 second period, twice, the second time spinning it significantly faster, will more current be induced during the second period? And would this apply to generators in wind turbines, etc.? Thanks.
  43. romsofia

    Does Electron spin generate electricity?

    Does Electron spin generate electricity? I know that with the electron spin generates a magnetic field, but does it generate an electricity? Thanks for any input!
  44. U

    Help Needed: Understanding Electricity & Electrostatic P.D.

    i am in total confusion to co-relate p.d of electrostatic and p.d of electricity. can somebody help me out?/
  45. E

    What makes work positive (electricity)

    I don't really understand the concept of what makes work positive or negative for example if 3 charges are brought together from infinite what is the work done on them? I am extremely confused about what make work positive and negative.
  46. A

    Project: get a sms when my electricity falls out

    Homework Statement I am in my first year electronics/ICT but have already successfully completed several courses about electronics, microcontrollers, programming, fysics... I have to make a project in my second semester and I am really interested in domotica, so that's why i want to do...
  47. P

    Questions regarding basic electricity and unit conversion

    I originally wanted to post this in the EE forum, but after seeing the sticky there, I decided that this might be a better place. 1. I got the whole thing about unit conversions (like from V to kV, move the decimal point 3 to the left -- the number becomes smaller by 10^3). Right now, we're...
  48. R

    Creating Electricity through Mechanical Rotation: The Electrical Generator

    to be more specific how can you make electricity by spinning a mechanism?
  49. zoobyshoe

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    In which direction did your physics text teach electricity flows? Please mention the country in which the school where you learned this was located. I think there may be differences based on location in the world.
  50. M

    Lift design -no electricity supply?

    Elevator design -no electricity supply? I hope someone can help me. I'm designing a building for uni that requires several lifts (elevators) which transfer bicycles and pallets vertically. My tutor suggested to look at energy efficient lifts. He mentioned that he had seen a lift, which...
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