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. dev_maghraby

    B The voltage between two points

    In electrical circuit there are three resistors and a battery connected in series. After the first two resistors, there is a point connected to the ground. Why is the voltage difference between the ground point and the positive of the battery not 10 volts? In that circuit, I think that the...
  2. S

    I qv x B force in electron's proper frame

    Can we describe / explain the B x v force in the electron's own reference frame without reference to relativistic invariants, 4-vectors, tensors et al? The aim would be to explain things like the following video without the notion of "field lines" that electrons and wires move through. But the...
  3. physicsdick

    Higher Chance to get Lightning Strike by Large Power Consumption?

    Assume there are two tall building with same height, and the materials are the same, having same distance away from the storm cloud. Will the one building with extreme high consumption of electricity cause higher chance to get struck by lightning than the one building without ? Thanks!
  4. M

    B How much electricity is required to create a magnetic field as large & strong as the Earth's?

    How much power (Megawatts) would it require if we were to create a magnetic field as large and strong as the Earth's magnetic field?. I haven't learned how to calculate this, but just curious.
  5. H

    Mechanical engineer, always dangerous around electricity...

    hello, I'm a retired mechanical engineer always puttering on something looking to expand my knowledge on electrical power and primarily home power generation in grid tied systems
  6. milkism

    Complex RLC Circuit Problem (System of diff eqs)

    The following circuit is: Going clockwise the current ##I_1## goes through resistor ##R_1## and voltage ##V_11##. Current ##I_2## goes through capacitator ##C_1## and ##R_2##. Current ##I_3## goes through resistors ##R_3## and ##R_4##. Current ##I_4## goes through resistor ##R_5##, but from...
  7. M

    Can I use a Stirling generator to make electricity from our wood fired stove?

    For the last few weeks I've been breaking my head over an efficient way to make electricity from our wood fired stove. We don't need huge amounts, but about 500 watts would be nice. I'm a retired engineer and I'm taking this on as a hobby really. I've gone through various ideas and iterations in...
  8. camptent

    B Extracting electrical energy from Orbital motion

    If the earth has been revolving around the sun almost perpetually, we should mimic this motion for electric generative purposes or is it not feasible?
  9. W

    Classical Finding the Right Physics Books for College: A Guide for Students

    Hi,I m studying for college and I need to receive some info from you guys. Which books should I use to study mechanics,thermodynamics,electricity and magnetism? I have no idea what books I should study because my own physics teacher has some pdfs in her USB and I can t borrow the USB because...
  10. Y

    Need a good link to learn V=IxR for my grandaughter

    Hi My grand daughter is a senior in HS, She even took AP physics and calculus, BUT she never learn simple electrical stuff, like the basic V= I x R. I want suggestion of some good links she can read about very basic electricity/electronics starting with V = I x R. Of cause I know all those...
  11. P

    Filmmaker and inventor fascinated by Physics

    Hi, my question is about electricity, hydrostatic pressure, potential energy and friction. Using an electrically powered compressor (such as compressors used to fill diving bottles) if I fill a tank of volume 10 cubic meters to a pressure of 100psi, 1. what is the potential energy stored in that...
  12. M

    Saltwater Pool/lightning Scenario for computer game

    TL;DR Summary: What would happen if a bolt of continuous lightning hit an enclosed saltwater space with someone swimming far below the surface? Hello! I'm actually asking this as a DM for a DnD campaign. One of my players trapped a bad guy within a large (30m/side) freestanding cube of...
  13. P

    Intro Physics Looking for a book that can help with conceptual understanding of elctromagnetism and electro magnetic devices

    So my neighbor is interested in electricity and magnetism. Well he's actually been watching youtube videos and thinks he can make some kind of free energy device. But anyways I thought it could be fun to do some real projects with him like playing with magnets, making a diy DC generator, and...
  14. casparov

    Calculate the Magnetic Vector Potential of a circular loop carrying a current

    Can someone explain what exactly happens at (4) ? I do not clearly follow, except that there is some cosine law going on? I also do not really understand why at (3), r' doesnt have a z hat component, but I can live with that.
  15. S

    Calculate the voltmeter reading for this circuit with 2 sources and 2 resistors

    I find the current first, which is 2 A. Then the voltmeter reading would be 10 V - 1 x 2 = 8 V. But the answer is 12 V. I don't understand why it should be 10 + 1 x 2 = 12 V Thanks
  16. K

    Calculating electric charge from graph (capacitor)

    Apparently, we need to integrate the functions from 0 to the time when it is fully charged. However, I integrated in terms of t so the soultion (according to a graph programme) should be around 236 Vs but I don’t see how this could help me.
  17. E

    I Meaning of "Static Electricity" and Physical Interpretation

    If a balloon and a sweater are rubbed together, high-school science teachers like to say "the electrons transferred to the balloon in the form of static electricity." Then, it is often charming to show that two such balloons repel one another "because they have more electrons." Can we unpack...
  18. Philip Koeck

    I Speed of Electricity in Plate Capacitor & Cable

    Consider a large, charged, plate capacitor with a distance of, let's say, 1 lightsecond between the two parallel plates and also a plain cable of the same length. Everything is in vacuum. If I first connect one end of the cable to one plate and then connect the other end to the other plate the...
  19. Steven Ellet

    Understanding and Interpreting Data from Static Electricity Meter Experiments

    My static electricity meter won’t stay zero when I am not moving and when I am electrically grounded. Video: EDIT: Can you see this? shorturl.at/jsGV0
  20. R

    Electricity from flared gas in oilfields

    Hi, I recently read the following article on BBC online: "Revealed: Huge gas flaring emissions never reported (https://www.bbc.co.uk/news/science-environment-62917498)". Can they not use the ‘waste’ gas from flaring to generate electricity? Is it not feasible or economically viable? Do they...
  21. kma

    I What happens to resistance of tap water as voltage is increased?

    1 In recent days I have done a few experiments measuring the current of water as it goes up from 9 volts up to 36 volts, and following Ohms law to convert it to resistance. And I discovered a very interesting trend. In between 9 and 18 volts, there is a massive drop in resistance (by around a...
  22. fluidistic

    What are ways to learn/play with electricity at 6 years of age?

    I would like to let my 6 years old son play and learn about electricity or electronics. I have searched on the Internet and what comes out are mostly kits with an arduino or a clone, which are very interesting but not exactly what I'm looking for. I have seen a kit that teaches about electricity...
  23. smiddleton26

    Misc. Expand balloon with static electricity

    The idea is to wrap a balloon in several layers of material, similar to that used in electrostatic adhesion wall climbing robots, and run power through the layers. The electrostatic charge on the layers outside the balloon will build up and the air inside the balloon will begin to become...
  24. T

    Calculating Electricity from Rainfall: A Project Guide

    Summary: I want to find out how much electric can be calculated from a certain amount of rainfall I am doing a project. I have estimated how much water I expect per month but I am not sure how to calculate the amount of electricity I expect to generate from this rain fall can someone give me...
  25. A

    I Did Ohm, Ampere, and Volta Collaborate on Ohm's Law?

    Voltage SI unit = Volts Current SI unit = Ampere Resistance SI unit = Ohm Ohm's law : V=IR Did Georg Ohm (German), Ampere (French) & Volta (Italian) collaborated when Ohm came out with this electricity equation with units for voltage, current & resistance as per their surnames? Credit goes to...
  26. G

    Can electricity enhance physical performance?

    I am comic fan There are several fiction character with electricity ability. Like Sasuke and Kakashi from Naruto , and Killua Zoldyck from Hunter X Hunter, they use membrane concept of electricity to cover their bodies, which helps the electric nerve pulses to run at the electrical membrane...
  27. Eobardrush

    Help in solving an electricity circuit problem involving Kirchoff's law

    My initial solving method was taking 1.75A and adding the resistors at the 1st loop(4 and 8 ohms) to get the answer V=IR V=1.75(4+8) V=21V But the answer sheet uses 0.75A instead of 1.75A to find EMF of E1. So according to the answer sheet its V=0.75(4+8) V=9V 0.75A is the answer for the i)...
  28. Steven Ellet

    Can Ancient Methods of Grounding Protect Against Static Electricity?

    I know there are straps with grounding wire(s) to protect sensitive equipment. I am trying to avoid being shocked by every doorknob I try to use. Right now I am just walking around barefoot to prevent this but that just leaves my feet cold. I have also tried using a piece of medal to reduce the...
  29. Shan43

    B How to find the current density in an alkaline electrolyzer?

    To my understanding, current density is simply the current flowing through the alkaline electrolyzer divided by the area (the units for current density are A/m^2). But what would the area be in this situation? Is it the area of the electrodes or maybe the area of the electrolyte solution or...
  30. A

    Trajectory of an electron traveling near a current-carrying wire

    B equals 50*10^-7 T (at first instance) Fm equals 8*10^-20 N (at first instance) I know Fm is perpendicular to the velocity, and I know the estimation of the trajectory (somewhat similar to the curve y=lnx). Since I think vertical velocity will be constant, only changing the x component, I...
  31. cellist542

    Hardest content to learn for AP Physics C: Electricity & Magnetism

    What are some of the hardest concepts to learn in AP E&M? I am going to prepare for the exam with my previous physics teacher. I am currently a senior enrolled in AP Calc BC, and I already took AP Mechanics.
  32. T

    I Static Electricity -- How best to generate it and use it?

    Hello friends, Was wondering, how would you go about charging an object with a lot of static electricity, and that I could hold. Just like if I had a balloon I just rubbed in my hair but, i don't know, 1000 times stronger... Is that possible, and if so, how could I achieve that ? Thank you...
  33. E

    How Do You Calculate the Radius of a Wire Using Electrical Resistance Formulas?

    i really have tried all the formulas out there and can't seem to get a solid answer
  34. xpell

    I What are the most energetic lightning "superbolts" ever measured?

    Hi! I would be interested in properly referenced data about the most powerful / energetic lightning bolts on Earth to get a good idea about their maximum possible order of magnitude (maybe depending on location?) Both direct measurements or indirect but well-founded estimates (e.g. satellite...
  35. S

    Shielding Dirty Electricity Ground Current

    Would using an insulator like rubber tires partly buried in the ground + partly protruding above the land surface to create a continuous perimeter around a piece of land possibly shield the land inside of it from the accumulation of charge on the surface of the Earth which occurs in the vicinity...
  36. Viona

    B The resistance of an ohmic conductor

    I know that the resistance of an ohmic conductor increases with length because the electrons going through the conductor must undergo more collisions in a longer conductor. But why decreasing the cross-sectional area of the conductor also increases the resistance of a conductor?
  37. P

    Why Can't Current Flow Between Two Same Voltage Nodes?

    The question is to find the resistance between points A and F. I understand that the resistor between OC can be removed. From this point onwards, resistor OC has been removed. Let the far right point of the diagram, where i5 and i7 exit from, be B. Is it possible to detach the remaining...
  38. S

    Convection current in electricity

    So, I randomly came upon this in a textbook that I was skimming and I think I have a very very surface ideea of what it's about but I want to read and know more in order to understand the fenomenon in much more detail. Any help in any form would be much appreciated! P.S.: This is my first post...
  39. amizy9990

    A copper wire contains 3.0 *10 ^ 22 number of charges on 1 meter wire

    A copper wire contains 3.0 *10 ^ 22 number of charges on 1 meter wire. What speed do the electrons move when there is 2 A current in the wire. t=q/t=3,20*10^3 C/ 2.0 A = 1,5*10^22 s v= 1m/1,5*10^3s= 6,6*10^-4 m/s
  40. P

    Stewart-Tolman Effect (Current caused by Acceleration of wires)

    Consider the inertial reference frame in which the positive ions forming the crystal lattice of some portion of a metallic ring are at rest. In this frame, an inertial force of mra exists. Consider the electrons in this portion of the metallic ring. The inertial force of mra is exerted on the...
  41. P

    Do charges always lie on the inner surface of capacitors?

    Parallel plates A, B are 5mm apart, with charges +1C and -1C respectively. Parallel plates C, D are 2mm apart, with charges +1C and -1C respectively. Capacitor CD is slid between capacitor AB. Find the potential difference between AB. The key idea to solving this problem is to suppose that +1C...
  42. P

    Difficult capacitance problem -- 3 long concentric metal cylinders

    A solution I found online claims that the effective capacitance between the middle and inner shell can be seen as: C (effective) = C1 + C2, where C1 is the capacitance between the inner and outermost shell, and C2 is the capacitance between the middle and outermost shell. Apparently C1 and C2...
  43. P

    Electrical energy stored by charged concentric spherical shells

    I thought up of this problem myself, so I do not have solutions. I would appreciate if you could correct my approach to solving this problem. Firstly, the charge induced on the inner surface of shell B is -q, and so the charge on the outer surface of shell B is Q+q. The energy stored can be...
  44. P

    Principle of superposition for charges/induced charges

    The key observation to solve the above problem is that the charge Q can be dragged out into a flat capacitor plate parallel to the 2 existing plates. Apparently, while the charge distribution on the 2 existing plates changes, the total charge induced on each plate remains the same, due to the...