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. D

    Can we transfer 100% Potential energy to electricity?

    I read somewhere PE=KE, how? It mean we can get transfer 100% PE to KE and KE to Joule Please anyone can explain? If I throw mass of 1000kg from 50 meters height can I get energy equal to Pe=mgh = 1000*9.81*50=490500 Joule? It mean 490500Kn = 490500watt= 490.50Kw. Is it possible to to get this...
  2. C

    Monitor restarts when I make an electric arc

    Why does my laptop's screen refresh every time I bring a metal object (any size) to my electric lighter? -Happens when I am 1 foot away from the laptop -1 foot away from the external monitor's wires (HDMI & power) 1. Video footage (MUST WATCH) NOTE: the laptop screen also flickers a bit NOTE...
  3. astroscout

    High Voltage Discharges or Explosions from Powerlines -- why these colors?

    Hi...Here is a GIF of some electrical explosions that I recorded with my full spectrum camera. These power lines supply power to a neighboring county so it didn't affect my area. In the upper atmosphere we see something similar in Transient Luminous Events (TLEs). In the case of the blue in Blue...
  4. Suyash Singh

    Electricity and Electric field

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  5. A

    Q: Generating Electricity with Charged Objects

    Hi guys i have a question i want an answer to let say i have an object that is negatively charged and another object positively charge and i connected them with a wires to a light bulb will they generate electricity and the object never lose their charge let's they they have unlimited charges.
  6. N

    Velocity of a charged particle as it approaches infinity

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  7. Cheesycheese213

    How do phone chargers work? (thin cable question)

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  8. H

    Find the transient current in this circuit

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  9. C

    RC Circuit with parallel resistor

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  10. Cheesycheese213

    Correlation between the cost to produce electricity and the cost to consumers?

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  11. Cheesycheese213

    Positive/negative electron transfer?

    Can a positively charged and negatively charged object charge by conducting? If so, is it possible to make a neutral charge again?
  12. M

    Elementary Charge: Explaining the Integer Multiple of e

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  13. A

    Verification of Ampere-Maxwell Law

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  14. J

    Engineering Circuit interconnection: power delivered

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  15. C

    How Do You Determine the Load Resistor Value for Maximum Power Dissipation?

    Homework Statement A constant voltage source V with internal resistance r is connected to a load resistor R. The dissipated power by the resistor R is P=RV^2/(R+r)^2. Show that the maximum power dissipated by the resistor R is achieved when R = r. The maximum of P with respect to R is achieved...
  16. radiant_june

    Electric field strength at a point between charges

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  17. kcombs

    Solve RC Circuit Problem: Find Time of Current > 50mA

    Homework Statement Suppose a 120 micro-farad capacitor from a camera flash unit retains voltage of 210 V when an unwary student removes it from the camera. If the student accidentally touches the two terminals with his hands, and if the resistance of his body between his hands is 1.8...
  18. B

    Does U=qV or -qV? I notice my textbook uses qV but

    Hi I have a question about electric potential! Since the negative sign isn't used in U=qV, and a-b is used for subscripts, then that takes care of the negative. But what about using U=-qV? An online lecturer uses U=-qV, while my textbook uses U=qV and then uses -qV to explain the force used to...
  19. doglover9754

    What is electricity made out of?

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  20. Zap, Crackle and Pop: The Story of Electricity with Dr. Marty Jopson

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    Dr Marty Jopson leads us through the story of electricity in a show buzzing with demonstrations. Have we tamed electricity? From the Ancient Greeks to Faraday’s genius, this show puts the awesome back into electricity.
    • Wrichik Basu
    • Media item
    • electricity
    • Comments: 0
    • Category: Electromagnetism
  21. R

    Why Does Current Produce a Magnetic Field But Not Vice Versa?

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  22. Low-Q

    Regenerating electricity on an e-bike

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  23. Y

    Uniform Electrical potential energy

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  24. T

    Can a radio frequency be lowered by a passive circuit?

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  25. sumit_1

    Understanding Charge Flow in RC Circuits: A Scientist's Perspective

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  26. M

    How Can Static Electricity Be Controlled in Textile Spinning Machines?

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  27. W

    Acoustic Electricity Generation - Modern Applications

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  28. C

    Quantifying Static Electricity Hazard with High Explosives

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  29. T

    How do I measure the "load" in a schematic?

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  30. M

    Questions about finding dBm values

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  31. C

    Dirty electricity and EMI filter

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  32. P

    What are the solutions for this electricity problem?

    Homework Statement Hey guys, here is a question that I have trouble with, it is a past paper question in the AS physics syllabus /Users/peterrong/Desktop/Screen Shot 2017-10-10 at 3.57.12 PM.png Homework Equations The Attempt at a Solution I have attempted using kirchhoff's laws, but the...
  33. I

    B We could lose electricity and satellites due to solar flares

    Hello, all! I found several sources which say that humanity could be in trouble because of solar flares! Scientists said that the Earth could be hit by solar flare within the next 100 years! Current costs of repair in the US could be up to 2.5 trillion dollars! It seems like Sun will punish...
  34. K

    Electric field model using a cylindrical capacitor

    Homework Statement In a lab experiment we measured the potential at different points within a cylindrical capacitor electric field modeling plate thing (apparently that's the best I could do to translate that into English). The positive electrode was connected in the middle and the negative...
  35. E

    Checking my answer.... finding the power of a current and a voltage source

    Homework Statement The current source and voltage source in the circuit shown in the Figure below are connected in parallel so that they both have the same voltage, vs. The current source and voltage source are also connected in series so that they both have the same current, is. Suppose that...
  36. M

    Question on corner and resonant frequencies

    Homework Statement 1. An RC filter is constructed by modifying a voltage divider. The top resistor R1 = 3kOhms remains the same but the bottom resistor R2 is replaced by a capacitor C = 8nFarads. Determine the corner frequency fc for this filter in kHertz. 2. For an RLC circuit R = 12.4...
  37. F

    Static Electricity and dc motor

    If take a simple dc motor and connect the negative side to let's say a insulated metal plate. The other side directly to ground and you then turn the shaft of the motor. Would you force all of the free (loosely using all) electrons in the insulated metal plate through the motor to ground giving...
  38. M

    Question About Duty Cycle and Average Value of a Square Wave

    Homework Statement [/B] 1. Using the Schematic of a 555 in astable mode from the Wikipedia entry on '555 Timer IC," resistor R1 = 8 kOhms and capacitor C = 3 micro-Farads. Determine the value of R2 so that the output duty cycle is D = 0.7. Note that D is not expressed as a percentage here for...
  39. Epoch

    Electricity: electric field in a point Between Two Charges

    Homework Statement I've seen many books writing the cosine rule like this: a^2 = b^2 + c^2 - 2bc cos A My electricity textbook for an electric field in a point between two charges says this: E resultant = root[E1^2 + E2^2 + 2*E1*E2*cos(angle between E1 and E2)] In the first equation it is -2...
  40. ISamson

    Electricity sources vs. fossil fuels

    Hello, The issue of climate change and energy has been in the news for a long time. But are electric, chemical or renewable sources really more environmentally friendly than fossil fuels? Fossil fuels need to be burned, which produces CO2, which retains the heat from escaping our atmosphere, so...
  41. M

    Question about Capacitance and Inductance

    Homework Statement [/B] Hey everyone, I recently got two problems on capacitance and inductance and need some help on them. Here are the two problems: 1. A Royal Red Robin Burger contains 1230 food calories. Also, more that the daily requirement for protein, fat, sodium ..., even without fries...
  42. U

    Does anyone understand where electricity comes from?

    I know that batteries move electrons therefore creating a current when there is a load. So if a battery is just for moving electrons, where do the electrons come from? Are electrons just in everything and by moving them you create electricity? If that were the case, why did I read somewhere that...
  43. K

    Inducing electricity w/ moving piece of metal, static magnet

    Hi! I'm curious to know, whether it is possible to produce electricity by moving a piece of metal over a magnet (i.e a immobile magnet and a moving piece of metal close to the magnet), and how this would be done in practice.
  44. S

    Resistors in Series - Lab data confusion

    Homework Statement (see my attached photo to better understand where I am coming from!) So after some research, I've discovered that the current at different points in a simple series circuit is supposed to be the same value, and that the voltage is supposed to be different values. I...
  45. S

    Resistors in Series - Lab data confusion

    Hi guys! (see my attached photo to better understand where I am coming from!) So after some research, I've discovered that the current at different points in a simple series circuit is supposed to be the same value, and that the voltage is supposed to be different values. I performed a lab on...
  46. ISamson

    Generating Electricity Chemically and Physically.

    Hello, I have been interested in making electricity by trying to construct small generators or taking advantage of chemical reactions. I have found a bike electric generator, but I did not know how to spin it constantly. I am looking for how to make electric currents of 8-20 volts for some home...
  47. D

    Would HE light applied to mercury vapor produce electricity?

    I'm likely going to have a ton of questions in the following weeks about a wide range of particle physics etc. If (electricity X mercury vapor) = light, then multiplication being transitive, (light X mercury vapor) = electricity. Can someone inform? I've found only mercury vapor as a metallic...
  48. M

    Can you make an electrophoresis battery?

    Can you immerse an electrolyte in an external electric field such that the ions are separated to a point that you could introduce electrodes and produce current in a load solely by virtue of the established charge distribution without electrode chemical interaction or galvanic potential as shown...
  49. C

    Motion of Charged Particles in Electric Fields

    Homework Statement This is the question: An electron at rest of mass 9.11 × 10−31 kg is accelerated through a potential difference of 350 V. It then enters some deflecting plates of 50 V with dimensions as shown. Calculate the distance x (deflection of the electron) (Charge on an electron is...
  50. B

    Why do experts refer to proton current as positive electricity?

    As an electronic engineering graduate, I was taught that positive electricity was the flow of "holes" created by the absence of electrons. These holes and the vector movement are modeled as the "positive" flow of electricity. Why then do I hear experts refer to proton current as positive...
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