What is Eletric field: Definition and 22 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. JohnnyLaws

    Finding the position where the electric field is zero

    This is the outline of the exercise I did on paper. So basically, my attempt to solve this involved writing the equations according to the reference frame I chose. The origin is the first charge. I began by putting the equations on paper: E = 0=> k*q*1/(x^2)+k*q*1/((x+d))^2 = 0, Note that 'x...
  2. G

    Gauss' Law - Electric Field for a Charged Metal Plate

    Homework Statement An infinite metal plate has a surface density of charge σL=-6μC/m² , Left side and a surface density Of load σR=+4μC/m² , in the right side. A Gaussian surface In the form of a circular cylinder, with area A 12 cm², is Located with the left side inside the plaque and a thin...
  3. S

    What is the magnitude & direction of the eletric field?

    Homework Statement Two +3.0nC charges are shown in the diagram below which are spaced 10cm apart. What are the strength and direction of the electric field at the position indicated by the dot in the figure (Figure 1) ? What is the electric field in N/C? What is the direction of the electric...
  4. Azura

    About electric fields (Symmetry)

    1) Imagine you have a clock but in each number you have a charge "q". If I have a test charge Q at the center, then by simetry, the net force on Q is zero. I imagined like, 1 cancels 7, 2 cancels 8, etc... But then, if I have a polygon with 13 sides, with a test charge Q, the net force also...
  5. T

    Motion of a particle in eletric field

    Homework Statement Hi guys. Just wondering if anyone could help me with Q7 part a) on the pdf I have attached below. I think my working are not correct but I can't see other way. If I add 6. and 7. together I would get an ans in terms of what the question is asking but I am not sure if that is...
  6. Especial

    Millikan Oil drop lab experiment - equation for speed of drop

    Millikan Oil drop experiment. For my current lab, we are recreating the milian oil drop experiment to measure the charge of an electron. However, we are using 1-micron diameter latex spheres in place of oil drops. Problem: I am having difficulty deriving an equation for the speed of the drop...
  7. L

    Really confused about voltage and some other quetions

    Please explain how or why (I have zero knowledge in physics).. 1. is Voltage the energy required by the elctrostatic forces between 2 points to move a certain quantity of charge between them? 2. Why is it called potential difference? Does this have to do with the difference in potential energy...
  8. D

    How Does Charge Distribution Affect Electric Field in a Ring?

    Homework Statement A Ring with center in (0,0) and R radius. The charge distribution from the ring is: ψ(θ) = ψo*Sin(θ), where θ is the angle from the x-axis (counterclowise). Negative values of the sine determine negative charge, and 0 no charge at all. What is the field (E) created from this...
  9. A

    A particle inside eletric field

    Sorry about my english , I'm still learning. I did it by energy, but i want to solve by integration QUESTION : A charged and massive particle runs with 66 m/s, 3^10-6 coulomb and 6^10-3 Kg towards a fixed particle with 4,5^10-6 coulomb, separated by 4,3 meters . What's the distance between...
  10. Z

    Electric Field and Acceleration for a Single Charged Plate and Capacitor

    Homework Statement I don't have any statement, i have to find the problem statement from the answers a) E = Q / [ Eo* (0.020 m)^2 ] b) a = E (1.60*10-19 C)/(1.67*10^-27 kg) = 2.0 *10^12 m/s^2 R=0,020 m q=1.60*10-19 C m=1.67*10^-27 kg Homework Equations F=ma => a=qE/m Gauss Law Integral of...
  11. K

    Quick question, eletric field of a conducting sheet of charges

    Hi one quick question about the electric field of a conducting sheet of charges. When you given a horizontal sheet of conductor with uniform distributed charge on its surface,will there be any electric field on the top AND on the bottom of the sheet? How is that different from a...
  12. C

    General Questions about Eletric Field and Eletric Potential

    Hi! I have already write everything on the pictures(In attachment), I have already circled the correct answer, however, I am not sure explain it correctly. So, can you check my explanation or question? Thanks!
  13. C

    Infinite Planes Eletric Field Question

    Hi! I have already write everything on the pictures(In attachment), I have already circled the correct answer, however, I am not sure explain it correctly. So, can you check my explanation or question? Thanks!
  14. C

    Concentric Eletric Field Question

    Hi! I have already write everything on the pictures(In attachment), I have already circled the correct answer, however, I am not sure explain it correctly. So, can you check my explanation or question? Thanks!
  15. Y

    An Electrostatics Problem - Eletric Field

    Homework Statement Question 2.2 http://www.studyjapan.go.jp/en/toj/pdf/08-007.pdf The picture is in the next page of the problem. k is the Coulomb constant. q+ is the charge at point A. q- is the charge at point B. AC = BC = CD = a Homework Equations E = kq/d² a² = b² + c²...
  16. C

    Energy Source of E Field in Decay of Neutral Pi Mesons?

    Suppose I have a large wall of neutral pi mesons, a lot of particles in a plane . And they decay into electron positron pairs and move in opposite directions to conserve momentum. Now we have created an E field in between the particles going from plus to minus. Now we have a parallel plate...
  17. S

    How Can an Electric Field Exist in a Conductor with Current Flow?

    electric field does not exist in conductors because it gets nullified due to polarization of conductor,but in current electricity the electric field is established in a circuit(conductor) which gives drift velocity to electrons for charge flow.how can electric field exist in a circuit? please...
  18. I

    Finding the magnitude of the eletric field of a uniformly charged rod.

    Homework Statement "A rod of 13.1 cm long is uniformly charged and has a total charge of -23.2 micro coulombs. Determine the magnitude of the electric field along the axis of the rod at a point 52.1575 cm from the center of the rod. The Coulomb constant is 8.98755e9 N M^2/C^2. Answer in units...
  19. A

    How can I calculate the electric field using the voltage and gradient?

    I listed all my problem in the file below I have figure out the V of that condition, but I do not know how to use E= -delV at this eg.
  20. P

    Eletric field within a cavity of a cylinder.

    Homework Statement Considering a cylinder of radius, R, and length D with uniform charge density p containing a spherical cavity of radius R/2. Find the field in the cavity. The cavity sits on one side of the cylinder so that it's diameter spans from the concave face of the cylinder to the...
  21. T

    Why must the eletric field inside a conductor equal ZERO?

    I was told that at electrostatic equilibrium, the electric field inside a conductor will be ZERO, so that the charges will not move any more. but why, I argue that, even when the electric field is not zero everywhere inside the conductor, there is still a chance for the charges to be...
  22. R

    Eletric field lines application

    I'm looking for some software that will allow me look at equipotential electric field lines for various structures in two dimensions. Any thoughts? I remember I ran into a good looking utility when I was researching antenna design, but now I can't find it...