Electric Definition and 1000 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.

View More On Wikipedia.org
Recent contents Top users
  1. TechTree

    Why did a 230v electric shock not hurt?

    Okay here's an example of what not to do when working with 230v... So I was about to repair some outdoor lights so I went to the circuit breaker panel and switched off all the power in that area for safety. I began to remove the light and disconnected the wires, then I was about to install the...
  2. L

    Derivation of the Potential Energy of an Electric Charge System

    Hi, I learned about how PE = U=kq1q2/r is the electrical potential energy for the system. It is found by taking the integral of electrical force and dr from infinity to the point of location we are interested in. So that is the intregral(F*dr) from r=inf to r=ro. My question is that do I...
  3. I

    Electric Fields and Electric forces help

    Homework Statement This is the question Structure opposite comprises 5 ions each of which has lost one electron. The sides of the square formed by the 4 outer ions are of length 0.2nm Ion E is at the midpoint 1.What is the force on A due to ion A?Homework Equations I'd imagine: F= kq / r^2...
  4. cookiemnstr510510

    Understand Electric Potential Energy, Difference & Potential

    Homework Statement My textbook is no help, my teacher is no help, so I've found myself here. I am having a difficult time understanding the differences in 1.Electric Potential energy 2. Potential Difference 3. Electric potential Im sure this question has been asked tons of times but I need...
  5. cookiemnstr510510

    Electric field from spherically symmetric charge distributio

    Homework Statement A spherically symmetric charge distribution produces the electric field E=(200/r)r(hat)N/C, where r is in meters. a) what is the electric field strength at 10cm? b)what is the electric flux through a 20cm diameter spherical surface that is concentric with the charge...
  6. cookiemnstr510510

    Electric field sphere calculations with a hollow cavity using Gauss' law

    Homework Statement A spherical cavity is hollowed out of the interior of a neutral conducting sphere. At the center of the cavity is a point charge, of positive charge q. (picture attached) a)What is the total surface charge q(int) on the interior surface of the conductor (i.e., on the wall of...
  7. cookiemnstr510510

    Electric field using Gauss' Law

    Homework Statement Two small insulating spheres with radius 9.00×10−2m are separated by a large center-to-center distance of 0.545 m . One sphere is negatively charged, with net charge -2.35 μC , and the other sphere is positively charged, with net charge 4.35 μC . The charge is uniformly...
  8. O

    How to fix this electric circuit

    Homework Statement I'm not sure if the construction of this circuit is correct, so that both lamps, which are the same, shine equally brightly. Otherwise only the resistors are given. If it's wrong, what else would it look like? And why?[/B] Homework Equations I guess the laws of Kirchoff...
  9. isukatphysics69

    Find the Y component of Electric field at a point

    Homework Statement The figure below shows a thin, vertical rod of length L with total charge Q. The indicated point P is a horizontal distance x from the one end of the rod. What is the electric field at point P. Express your answer in component notation in the two blanks below. L = 5.0 cm, Q...
  10. isukatphysics69

    Find electric field a distance P from a charged rod

    Homework Statement The figure below shows a thin, vertical rod of length L with total charge Q. The indicated point P is a horizontal distance x from the one end of the rod. What is the electric field at point P. Express your answer in component notation in the two blanks below. L = 5.0 cm, Q...
  11. isukatphysics69

    What is the magnitude and direction of the electric field

    Homework Statement What is the magnitude and direction of the electric field at the position indicated by the dot in the figure below? Give your answer in component form in the blanks below. What is the x-component of the electric field at the indicated point? Homework Equations kq/r^2 The...
  12. cookiemnstr510510

    How Is Electric Flux Calculated for a Rectangle in an Electric Field?

    Homework Statement A 2cm x 3cm rectangle lies in the xy plane. What is the electric flux through the rectangle if Electric field= (100i +50k) N/C Homework Equations Φe=E⋅Acosθ (Electric Flux Equation) The Attempt at a Solution My question is to find the magnitude of the electric field we...
  13. smallville2010

    Electrical Device for Electric Scooter, to get the speed?

    I want to do an application that can connect to my Electric scooter (the kind you stand on) and can get a speed and engine temperature readings, i'm looking into a device i can attach to the wheel or a temperature gauge i can attach to the engine and get a reading from both of them something i...
  14. José Ricardo

    About the efficiency of engines

    if we had an entire car made of Starlite (a material that was created resistant to 18032 °F). Would the efficiency of the combustion engine be close to that of the electric and that of the electric would be almost 100% efficient? https://en.wikipedia.org/wiki/Starlite
  15. J

    Electric field as a function of time

    Homework Statement Before diving into the quantum-mechanical superposition principle, let’s get some practice with superposition in classical physics. Consider an electromagnetic wave propagating in the z-direction, which is a superposition of two linearly polarized waves. The electric field...
  16. Another

    Problem about electric potential and power transmitted down a cable

    When to use ## V =-\int E ⋅ dl ## or ## V =\int E ⋅ dl ## ? When i use ## V =-\int E ⋅ dl ##. i can not show that P = IV because ##\frac{ln \frac{b}{a}}{ln \frac{a}{b}} ≠ 1## But the solution use ## V =\int E ⋅ dl ## I'm concerned about using "minus" .
  17. cookiemnstr510510

    Electric field of bent non conducting rod

    Homework Statement You are given a non conducting rod carrying uniformly distributed charge, -Q, that has been bent into a 120° circular arc of radius, R. The axis of symmetry of the arc lies along the x-axis and the origin is at the center of curvature of the arc. (a) in terms of Q and R...
  18. cookiemnstr510510

    Electric field of concentric rings

    Homework Statement Derive the electric field a distance, z, above the center of a single uniformly charged ring of radius, R, with a linear charge density, λ. You are now given two uniformly charged concentric rings. The inner ring has radius, R, and carries a uniformly distributed total charge...
  19. cookiemnstr510510

    Electric field above a disk that equals half the max electric field

    Homework Statement At what distance, a, along the axis of a uniformly charged disk of radius R is the axial electric field strength equal to one half its value at the surface of the disk at the center. Homework Equations electric field of disk (attached) The Attempt at a Solution First I...
  20. U

    Electric potential of an electron in a capacitor

    Why is the electric potential of an electron in a capacitor measured from the negative plate and not the positive plate here? This is from Liboff Introductory quantum mechanics 1st(current is 4th) edition: I don't understand why the distance z is measured from the bottom plate if the...
  21. cookiemnstr510510

    Electric field of ring of charge/washer of charge/disk of charge

    Homework Statement Homework Equations charge density equations, electric field equations, The Attempt at a Solution My attempts are attached. The attachment labeled A, is part A. Part B took a lot of paper so there are two attachments labeled B1 and B2. It is really B and C that I am...
  22. J

    Power required to compress air in a gas turbine

    I'm looking for advice on how much power is required to compress air in a gas turbine engine - parameterised by degree of compression and mass flow. Normal gas turbine engines have exhaust turbine(s) on the same shaft as the air compressors. They bleed some of the exhaust energy to drive the...
  23. Captain Levi

    Someone help explain electric dipole situation

    Ok so she says that electric dipoles are of opposite charge but equal magnitude at 3:40. But then at 5:33 she shows 2Q with -Q, at that point the magnitude of the 2Q particle wouldn't be equal to the -Q so they wouldn't be electrical dipoles right?
  24. nashikin58

    How to avoid a clash of magnetic charge and electric charge

    Hi, now I'm working on a project which involves a dc motor and high voltage. I'm developing a machine consists of a motor to rotate a platform disc and high voltage will be applied during the rotation. The problem is when I supply a positive high voltage at motor shaft during rotation, the motor...
  25. eudesvera3

    Paradox of a convergent nozzle fed by an electric fan

    Let us assume we have a cylindrical wind tunnel having a 0.5 m diameter fed by an electric fan. The cross-sectional area of the wind tunnel would be A1 = (PI/4) D1^2 = 0.196349541 m2. Let us suppose the motor driving the fan has a power rating of 1,500 W. At this stage, let us assume that the...
  26. C

    Electric Field Force Exerted Vertically

    Homework Statement A proton enters the uniform electric field produced by the two charged plates shown below. The magnitude of the electric field is 4.0 × 105 N/C, and the speed of the proton when it enters is 1.5 × 107 m/s. What distance d has the proton been deflected downward when it leaves...
  27. J

    Electric and Magnetic field acting on an electron

    Homework Statement In the figure, an electron of mass m, charge − e, and low (negligible) speed enters the region between two plates of potential difference V and plate separation d, initially headed directly toward the top plate. A uniform magnetic field of magnitude B is normal to the plane...
  28. J

    What happens to the current when an electric motor slows to a halt?

    If a motor slowed to a halt, will the current go up or down
  29. L

    Calculate the charging time for my Electric Vehicle

    So cars usually specify the batteries in kWh (rather than Ah). So given that i know the kWh capacity of a car. I also know the charging effect in W (i.e. the voltage and amps in my charging station). Can I reasonably estimate the time it'll take to charge the battery? It doesn't have to be...
  30. Physics Dad

    Finding the electric field of insulated shell

    An insulating spherical shell of inner radius r1 and outer radius r2 is charged so that its volume density is given by: ρ(r) = 0 for 0 ≤ r < r1 p(r) = A/r for r1 ≤ r ≤ r2 p(r) = 0 for r > r2 Where A is a constant and r is the radial distance from the center of the shell. Find the electric...
  31. Jozefina Gramatikova

    Conducting sphere Find the electric filed for r<a,a<r<b,r>b

    Homework Statement Homework Equations The Attempt at a Solution for part ii) a<r<b E=0 I am not sure what will be the difference between the formulas for the electric field for a<r and a>b I think the formulas will look the same: The only difference that I can think of is that when r<a...
  32. A

    Electric field distribution in the brain

    I have a PhD in Molecular Neuroscience but am working on something that requires knowledge of electric field distribution in the brain. I understand that electric field intensity (V/cm) is E=(V1-V2)/d in a theoretical model (between 2 infinite plates, that are parallel and equidistant through a...
  33. D

    Electric Field of a Non-Uniformly Charged Sphere | Homework Help

    Homework Statement A solid isolated sphere with radius R has a non uniform charge which is given by ρ= Ar², with A a constant and r<R measured from the centre of the sphereHomework Equations (a) Show that the electric field outside the sphere is equal to E = (AR5)/(5ε0r²) (b) Show that the...
  34. R

    Complete screening of an Electric field?

    Hi, I have difficulty understanding the term screening. Screening is reducing of the electric field, as far as I have understood until now. 1. Why does screening occurs? Is it due to collective interaction of plasmons? 2. If we have a slow electric field, will screening occur or will it not...
  35. S

    Is the Electric Displacement Field Zero at the Boundary?

    Hello, I'm going through electrodynamics by griffiths.. I'm unable to understand the case 1) for no free charge and 2)when curl of P(polarisation ) is zero at the boundary Then what can we comment about D the displacement field having both it's divergence and curl zero at the boundary. Please...
  36. Krushnaraj Pandya

    Potential difference in uniform electric field

    Homework Statement There is a uniform electric field=100 V/m inclined at 45 degrees with the x axis. My doubt boils to which is greater? V(0,0) or V(10√2,0) (since my answer has the wrong sign) Homework Equations All electrostatics formulas The Attempt at a Solution The work done to move a...
  37. Krushnaraj Pandya

    Electric field and potential at vertex of cube

    Homework Statement A solid non-conducting cube of side l and uniformly distributed charge q, has electric field E and potential V at one of its vertex, imagine this cube to be made of 8 smaller cubes of side l/2. if one such cube is removed, find the new field and potential at the point where...
  38. Mirza Danish Baig

    Electric field between conducting and non-conducting sheets

    Homework Statement Two infinite sheets of charges are placed parallel to each other. If the sheet on the left is non conducting and have a uniform charge density 3(sigma) and the one on the right is conducting and has a uniform charge density (sigma). If the area on both plates is 1m^2 then...
  39. Muhammad Usman

    Capacitor Electric Field in a Dielectric?

    Hi, I was reading the capacitor and its operation and it is written there that when the DC is applied to the capacitor it becomes open circuit. The main mechanism behind this phenomena is explained as below:- "When DC voltage is applied the charge started accumulating on the plates of the...
  40. S

    Fundamental confusion about THREE-PHASE electric power setup

    Homework Statement Hello to everyone who's reading. :) I hope I posted this in the right place; while this is not exactly a homework problem, I am trying to improve my understanding of the background information before proceeding with course-style problems. This post is because I'm trying to...
  41. F

    Basic question about current in an electric circuit

    Let's say we have a basic electric circuit consisting of a battery with some potential difference, and a loop of wire. The wire loop also has some segment with a higher resistance. Now since there is a potential difference, the free electrons will move to make the circuit equipotential. The...
  42. shahbaznihal

    Spatial dependence of induced Electric field

    The Faraday's law and Lenz's law together give you, $$\xi = -\frac{\partial\phi_B}{\phi t}$$ or put another way,$$\vec{\nabla} \times \vec{E} = -\frac{\partial \vec{B}}{\partial t}$$. My question, I am just asking to make sure, the spatial dependence of ##\vec \nabla \times \vec E## will be the...
  43. A

    Gauss' law: find the electric field

    Homework Statement A long, thin, straight wire of length 1.3 m has a positive charge 4.1 × 10-8 C distributed uniformly along it. The electric field created by this wire at a radial distance 3.2 cm has a magnitude of ε= 8.85E-12 Homework Equations I think I need to use E= q/(4πr^2ε) but I...
  44. D

    Why electric field is always perpendicular to equipotential?

    I have some understanding, but I'm not sure about how accurate it is: Electrostatic force is given by F = qE, where F and E are both vector quantities. If the dot product of either side and the displacement vector Δs along an equipotential line is taken, the equation becomes F⋅Δs = qE⋅Δs. F...
  45. J

    B Electric Field in Accelerating Elevator

    According to an inertial observer the electric field of a charged ball sitting on the floor of an accelerating elevator is contracted more than the elevator is contracted. So the inertial observer concludes that an observer inside the elevator will measure that the Coulomb-force from the ball is...
  46. S

    Is Griffiths' formula for electric dipole radiation correct?

    Hello! I am reading Griffiths derivation for the electric dipole radiation (actually my question would fit for the magnetic dipole radiation too). He considers 2 charged balls connected by a wire with charge going back and forth between them. Now, when he calculates the vector potential he uses...
  47. M

    Electric racing -- Custom 4WD Electric Race Car Advice Please

    [Mentor's note: two threads on the same topic have been merged] I live here in Stephenville, TX and currently going to Tarleton for Civil engineering. A bit rusty and new to electrical components. But anyways, here in town lawnmower racing is kind of a big event. Many of us have 600cc crotch...
  48. H

    Speed/acceleration calculations for an Electric motorcycle

    Good day all, This is my first post here, hope you all are able to help me out here. I am thinking about converting an old Suzuki GS500E from an internal combustion engine to an electric motor. At the moment I am having some difficulties with the physics side of things, I would like to...
  49. A

    Electron speed and acceleration in an electric field

    Hi everyone, I often work on a SEM, a type of microscope which is based on electron acceleration between an electron source and the sample you are working on. For this reason and since a few weeks I was wondering how an electron (in term of speed) behaves in a constant and linear electric field...
  50. Zahid Iftikhar

    Electric Potential midway between a pair of equal opposite charges

    Hi I need help to understand how electric potential could be zero at the center of two equal but opposite charges. It seems, there is a no field free region anywhere inside the space between the charges. If I move a test charge from negative to positive charge or otherwise, there seems to be no...
Back
Top