What is Electric: Definition and 1000 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.

View More On Wikipedia.org
Recent contents Top users
  1. KC374

    Work Done by an Induced Electric Field

    I have drawn a picture of what the induced electric field will look like, and I have determined its magnitude both within and outside of the magnetic field. I was able to get the right answer for part (b) with this information, but I don't understand why the answer for part (c) is 0 J. It...
  2. P

    Electric field due to a straight rod

    The net electric field is ## 2dE \cos\theta ## ## dE = \lambda dx/(4\pi\epsilon (x^2 +r^2)) \\ 2dE \cos\theta = 2r\lambda dx /(4\pi\epsilon (x^2 +r^2)^\frac 3 2) \\ E_{net} = 2\lambda r /(4\pi\epsilon) \int_0^a dx /( (x^2 +r^2)^\frac 3 2) \\ E_{net} = 2\lambda r /(4\pi\epsilon) [\frac x...
  3. Zero

    Calculating Electric Field: A Failed Attempt

    I tried getting E by dividing volts and distance since I know the distance between the two plates is .352 m but it did not work
  4. P

    Electric Field of a Point Charge and Thin Ring: A Comparative Analysis

    I thought it was easy but i am not getting the correct answer The electric field due the point charge q is ## E1 = q/(4\pi\epsilon x^2) ## The electric field due to the thin ring of radius R is considering the electric field due to the element charge dq (dS) ## dE2 = dq/4\pi\epsilon (x^2 + R^2)...
  5. F

    The orgin of the superposition principle of electric field

    Isn't the superposition principle of electric field just force being addable? Jackson's electrodynamics says it's based on the premise of linear Maxwell's equations. Which support(s) the superposition principle?
  6. V

    Is an electric superheater radiant or convective?

    Hello everyone, I am dynamically modelling a electric superheater. During the calculation I need to calculate the overall heat transfer coefficient. Can someone tell me which calculation do I need to use to calculate the overall heat transfer coefficient, radiant or convective? Please clear my...
  7. C

    Parameterize Radial Vector of Electric Field due to Spherical Shell

    Homework statement: Find the electric field a distance z from the center of a spherical shell of radius R that carries a uniform charge density σ. Relevant Equations: Gauss' Law $$\vec{E}=k\int\frac{\sigma}{r^2}\hat{r}da$$ My Attempt: By using the spherical symmetry, it is fairly obvious...
  8. E

    Ambiguity when taking the Earth as a zero for electric potential

    When you ground something in electrostatics, the potential of that body becomes the potential of the Earth once equilibrium has been reached. In this context, it is usually taken that the Earth is at 0V. There are two possibilities for this. Either the constant of integration is chosen such that...
  9. cwill53

    Why are my force equations giving me incorrect answers?

    I had made equations for the forces in the x-direction and y-direction, but when solving them they yielded the wrong answers, which makes me think that they were incorrect:##(T_{A}cos60^{\circ}+T_{C}cos45^{\circ})=0## ##(T_{A}sin60^{\circ}+T_{C}sin45^{\circ})=5lbs## Here's the diagram for the...
  10. Astronuc

    History Modern history of diesel-electric and electric locomotives

    I recently came across some good histories of GE and ALCO locomotives. ALCO was the second of the two preeminent steam locomotive manufacturers, the other being Baldwin. Diesel-electric locomotives were replacing steam locomotives, although steam continued through the 1950s, especially on...
  11. P

    Calcualtion of electric potential and radioactive decay

    This is just a representative diagram to visualize Surely a very tough one for me to solve. The number of nickel atoms are not mentioned. if the number of decays are ##3.78∗10^8## and with each decay depositing 100keV. The total energy deposited is ##100keV∗3.78∗10^8=6.048∗10^6## I have to...
  12. Achintya

    What is the reality of the Electric Force & Field?

    Please help. Thank you.
  13. G

    Find the Electric potential from surfaces with uniform charge density

    I do not have the solutions to this problem so I'm wondering if my attempt is correct. My attempt at solution: We have two surfaces which we can calculate the area of. I think we can use gauss law to find the electric field and then integrate the E-field to find the electric potential. So for...
  14. B

    Electric Force and Field homework problem

    This is my homework. And we don't have online lessons. But my teacher gave this for homework. I couldn't solve this problem. Can you help me?
  15. T

    Why will 240 volt condenser kill me but not 7,000 volt electric fence?

    I used to attend an HVAC program at a trade school. One time my instructor and i were working on either the outdoor unit of a split-system heat pump or the condenser of a split-system straight air-conditioner. Even though the unit we were working on was either an "outdoor unit" of a heat pump or...
  16. P

    Electric field in the Spherical Cavity

    a. For the question a the solution is If the uniform charge density is ρ then the charge of the sphere up to radius r is q = ρ * (4/3)*π * r3; Hence the electric field is E = (ρ *4π*r^3)/(3*εο*r^2); E = (ρ*r)/(3εο); b. I don't understand what is superposition? How to proceed? Please advise.
  17. EsinDerin

    Electric Field's Force on a Suspended Plastic Ball

    Hi,I couldn't do this problem.I hope someone could help meths is my first time in this forum
  18. Bilbo B

    Electric potential of a spherical conductor with a cavity

    Summary:: If the conductor is having a cavity and is provided with some charge, with the cavity too having some charge then how the potential will be affected on the outer surface of the conductor. The center of cavity and the center of hollow sphere does not coincide. As if their centers do...
  19. M

    The vector sum of the electric forces exerted on a particle

    r_{13}=r_{23}=\sqrt{(30*10^{-3})^2+(90*10^{-3})^2}=\sqrt{9*10^{-3}}\\ F^E_{13}=F^E_{23}=9E9\cdot\frac{5*10^{-9}\cdot3*10^{-9}}{9*10^{-3}}=1.5*10^{-5}\\ \theta=tan^{-1}(\frac{90*10^{-3}}{30*10^{-3}})=71.565\,degrees\\ \vec{F}^E_{13}=<F^E_{13}cos\theta, F^E_{13}sin\theta> = <4.743*10^{-6}...
  20. D

    Torque calculations for a small electric vehicle

    Hello guys, I'm trying to calculate the torque for a 3 wheeler electric (small vehicle). 2 driving wheels and one driven wheel. At the driving wheels we have a BLDC motor for each wheel. We want to calculate the torque for resting( not going down hill) on inclined plane (angle={5,10,15...
  21. D

    Exploring the Interaction of Magnetic and Electric Fields

    Hello, If you have an appropriately oriented conductive ring in a constantly changing magnetic field, current will flow in the ring. There will also be a magnetic field associated with the current in the ring. I understand (maybe ... ) that the current is due to the electric field which is...
  22. G

    Electric field around a sphere with an internal charge distribution

    I'm just going to skip some of the step since I only need help with understanding the last part. After rearranging the equation stated at "Relevant equation" (and skipping some steps) we will get: E * 4*pi*e0*R^2 = integral pv * 4*pi*R^2 dR E = 1/(4*pi*e0*R^2) * 4*pi * integral pv*R^2 dR E =...
  23. Bell

    What's the direction of electric field in Laguerre-Gaussian beams?

    As for Laguerre-Gaussian beams, the direction of wave vector is helical, and how about the direction of electric field? I found that there was little literature mentioned this.
  24. Jackoyo

    Solving Electric Field & Potential: Jack Needs Help!

    Hi everyone, I have abit of trouble with this question. Please help! Given charges +q, +2q, −5q and +2q are placed at the four corners ABCD of a square of side a, taken in cylic order from the bottom left corner. Find the electric field E and the potential V at the centre and verify that they...
  25. P

    MATLAB Creating the Electric Octupole Tensor of a cubic electric octupole

    I created an array, where the first three entries of each column are the x,y, and z coordinates. The last entry in each column is the charge. I called this array PCQ. l/2 l/2 -l/2 -l/2 -l/2 l/2 l/2 -l/2 -l/2 l/2 l/2 -l/2 -l/2 -l/2 l/2 l/2 l/2 l/2 l/2 l/2 -l/2 -l/2 -l/2 -l/2 q -q q -q q...
  26. V

    Motion of a Proton in Electric and Magnetic Fields

    a) 248*10^3 eV for 248kV Calculate the energy in J K=248*10^3*1.6*10^-19 =396.8*10^-19 J b) K=(1/2)mv^2 v=sqrt(2k/m) =sqrt((2*396.8*10^-19)/1.67*10^-27) =218^10^3 m/s c) r=mv/qB =1.67*10^-27*218*10^3/1.6*10^-19*1.5*10^-4 =15.17 mr=mv/qB...
  27. Z

    Electric field direction on a grounded conducting sphere

    I am required to find the direction of the electric field on the surface of a grounded conducting sphere in the proximity of a point charge ##+q##. The distance between the center of the sphere and the point charge is ##d## and using the method of images we find that the charge of the sphere is...
  28. Leo Liu

    Understanding the Electric Field of a Charged Sphere

    This page claims that "[t]he electric field outside the sphere is given by: ##{E} = {{kQ} \over {r^2}}##, just like a point charge". I would like to know the reason we should treat the sphere as a point charge, even if the charges are uniformly distributed throughout the surface of the...
  29. jisbon

    Electric field in Energy Bands

    This is my attempt at this question, and I'm probably wrong, will need some help/guidance from the experts here :/ i) (ii) Since energy band given by ##6.67x^2##, can I assume that electric field is simply the energy difference from 0-3m divided by 3m? In this case, would the answer simply be...
  30. S

    Does ECO mode in electric cars make sense?

    I just saw a video about an electric car which has an ECO mode. In ECO mode the car has less power. So let's say in normal mode the car has 100 kW and in ECO mode 60 kW. But why should the range of the car be greater if it has less power? Because as far as I know to reach a speed of v it...
  31. A

    How can we deduce the kink effect in the electric field?

    Hi. In videos online the kink is explained as a delay in the electric field when charges accelerate. Does this mean we can deduce the existence of kinks from coloumb law. Does the simple form of plane electromagnetic waves which is well treated in most books really exist. What is the...
  32. T

    Electric field within the cavity of a hollow conductor polarized by external charges?

    Suppose we have a hollow metallic conductor, just a thin metallic shell forming a large hollow cavity. It is then polarized by electric charges placed nearby externally. The equilibrium electric field must be parallel to the surface normals of the shell, there must be no tangential component...
  33. G

    Engineering Calculating the total electric field from two charges

    a) Should be pretty straight forward, from the equation E = kQ/R , we see that scaling is simply 1/R. b) Here is gets a bit trickier. We know that q acts as a source (E-field points outwards) and -q acts as a sink (E-field points inwards). If the distance is far away do we consider the Q1 and...
  34. B

    Deflection distance for an electron beam in an electric field

    Have tried doing this question but I'm a bit confused on where I'm going wrong This is what I have done but get a value that doesn't match to any of the options given above? Any help would be really appreciated, Thanks!
  35. K

    Calculate the current in all parts of this electric circuit

    In the circuit below, the output is 23 W across the resistor with the resistance 6 Ohm. Calculate the amount of current in all parts of the circuit as well as the polarity and EMF ε of the unknown battery. Circuit: My attempt: I get 6 unknowns with 5 equations. I don't know how to find the...
  36. Stephenk53

    Electronics Sites/companies used for electric parts

    Hello, I am building a battery pack to charge my laptop cooling pad and I am looking at batteries for it. I decided on LiPo because it is thin and thus should fit better on the cooling pad. I do not need help with the design since I am planning on using pre-made parts (although if you are...
  37. CrosisBH

    Trouble with Electric Potential Boundaries (Computational Physics)

    This is in python: #ELECTRIC POTENTIAL from mpl_toolkits.mplot3d import Axes3D from matplotlib import cm import numpy as np import matplotlib.pyplot as plt dx = 0.1 dy = 0.1 xrange=np.arange(-1,1,dx) yrange=np.arange(-1,1,dy) X,Y = np.meshgrid(xrange, yrange) max_dV = 10e-5 blockRadius = 3...
  38. rude man

    How to Recognize Split Electric Fields - Comments

    Continue reading...
  39. Adesh

    Will the induced electric field be circumferential?

    Let’s say we have a right handed Cartesian system and magnetic field goes in positive z direction, and let’s assume that the magnitude of magnetic field varies with time. Now, if I draw a circle with radius ##r## in the ##x-y## plane and let the magnetic field pass through it and vary with...
  40. H

    Electric field from a charge q1

    Hi, I have a charge q1 = -10 * 10^9. The the coordinatesare (3,4)m. I found the electric field vector that is (-2160i -2880j) n/c. My questions is if I add a charge q2 to the the coordinates(0,0) is the electric field stay the same?
  41. jim mcnamara

    Protein nanowires + Geobacter + humidty = electric potential

    https://phys.org/news/2020-02-green-technology-electricity-thin-air.html I am not competent to judge this (what seems very edgy to me) article. Basically it says: a ten micron thick protein layer with Geobacter on the surface and protein nanowires arranged in a mesh, when exposed to...
  42. S

    Why is the Answer C? Electric Field in Conductors

    The answer according to the key is C. I thought the answer would be E since the electric field inside a conductor is always zero. Can someone explain why the answer is C?
  43. threeonefouronethree

    Poisson's equation: Calculating the Laplacian of an electric potential

    First I calculated the electric fields outside of the sphere in terms of the total charge Q. total charge Q: Q = aπR^4 electric field outside: (r>R) E(r) = (1/4πε) Q/r^2 (ε is the vacuum permittivity) electric potential...
  44. P

    Plotting the Poynting vector of a radiating electric dipole [matlab]

    I've attached a .txt file of my script for those who want to take a look at it Here's a picture of my vector field at time t = 0 I'm very concerned about this picture because from my understanding the Poynting vector is supposed to point outwards and not loop back around, this looks nothing...
  45. S

    Location where the electric potential is zero between charges

    a) I take "a point where it is neutral" as the electric potential at that point is zero. Is this correct? And because the two charges are both negative, there can not be any point where V = 0? Am I wrong or maybe one of the charge should be positive? Thanks
  46. Quentief

    The Poulcen Arc: Exploring the First Electric Oscillator

    Hi everyone 🙂 I have read this article about the arc converter, also known as the Poulcen arc. https://en.m.wikipedia.org/wiki/Arc_converter It was apparently one of the first electric oscillators. Apparently, an electric arc was produced between two electrodes to put in resonance a RLC...
  47. Quentief

    Drawing Electric Arcs at 230 Volts

    Hi everyone :) I open this discussion because I would like to know how electric arcs are able to be drawn. Indeed, I have been told that it is perfectly possible to draw electric arcs at very low voltage, by simply putting in contact two electrodes and then drawing them apart. I wanted to try...
  48. F

    Electric field Difference between Electrostatics and Electrodynamics

    Hello everyone, I have been pondering on the behavior of the E field in conductors. In electrostatics (where the charges are not moving): a) Electric fields are time- independent but position-dependent b) Electric fields are always zero inside a charged or uncharged conductor. At the...
  49. moeug1999

    Electric Potential at A and B: Find the Answer

    I found the potential at A, however I tried doing it with B but it says I have the wrong answer.
  50. M

    Inducing electric current in a wire (a comparison)

    Consider the following experiment: from a lacquered copper wire we cut off twenty to thirty pieces of about 10 cm. From them we form a bundle of parallel wires and connect the two ends with one more wire each. The other ends of these two wires are connected to a sensitive analog ammeter. We hold...
Back
Top