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.

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  1. F

    Battery Powered Electric Motor and Charging Requirements

    I need to build a battery system to drive a 10 HP pump motor. The actual BHP varies as the pressure in the system rises, but for the most part we are operating at a 10.1 brake horsepower. Run time requirements will vary from a few hours to many hours. I settled on 8 hrs as a basis. Motor...
  2. TechieDork

    Find an expression for a magnetic field from a given electric field

    Here this is my attempt : Reference Textbook : Zangwill's Modern Electrodynamics I stuck at the last step , I really have no idea what to do next.
  3. A

    Finding a good descriptive model of the electric circuit (for 8th graders)

    Since this quesstion popped up in this thread I thought it might be better to create a new thread: https://www.physicsforums.com/threads/a-question-about-an-electrons-movement-in-a-dc-circuit.997736/ The question is the following: What kind of descriptive model could/should one use while first...
  4. A

    Electric Field from Non-Uniformly Polarized Sphere

    Solving for the volume and surface bound charge densities was easy using equations 1) and 2). The polarization only has an r component so ##ρ_b=-\frac 1 {r^2} \frac {d} {dr} (r^2 \vec P)=-α(n+2)r^{n-1}##, and ##\hat n=\hat r## so ##σ_b=αa^n##. To find ##\vec E## I intend to use equation 3)...
  5. PhysicsTest

    To find the parameters of velocity in an electric field

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  6. A

    Who invented electric potential and why?

    Why was that concept necessary ?, I know there's also a gravitational equivalent of this concept I couldn't find anything on google Thanks Daniel
  7. badluckmath

    Electric Field of two line charges

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  8. J

    What effects does an electric field have on potential energy?

    Like an electric field is applying a sort of force on a particle. I was wondering if this at all impacts the potential energy of a particle. For instance, when the force of gravity does work on an object, its potential energy changes as a consequence. Would it be the same thing here?
  9. S

    Converting a Lawn Tractor to Electric Power

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  10. PhysicsTest

    Find the electric field from charge density

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  11. B

    Understanding the electric field of a sphere with a hole

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  12. greg_rack

    The electric field between two adjacent uniformly charged hemispheres

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  13. Kaguro

    Poynting vector and electric field

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  14. PhysicsTest

    Power Calculation of general electric circuit

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  15. greg_rack

    What is the physical significance of torque being a vector in an electric motor?

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  16. P

    Electrostatics - electric potential and field strength (dielectric)

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  17. R

    Electric Fields with Motional EMF

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  18. A

    Electric Circuit: Path of Least Resistance

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  19. G

    Find the electric field from polarization

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  20. C

    Different types of electric motors

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  21. B

    I Searches for electric dipole moments (EDM) in atoms

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  22. greg_rack

    Final electric potential difference in a circuit with two capacitors

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  23. E

    Engineering Electric Power Systems book recommendation

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  24. Vossi

    Electric Circuit Differential equation help

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  25. P

    Electrostatic - electric potential due to a point charge

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  26. P

    Electrostatics: Calculate the Electric Field near a Charged Ring

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  27. greg_rack

    Electric potential difference at the ends of a resistor

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  28. huszarerik

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  29. J

    I Is the electric field of an atom a superposition or mean of electron positions?

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  30. yyfeng

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  31. greg_rack

    Clarifications about electric potential and potential difference

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  32. E

    The electric field inside a hole inside a conductor is still 0?

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  33. rude man

    Introduction to Electric Vector Potential and Its Applications

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  34. willDavidson

    Electric field of a point charge

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  35. willDavidson

    Electric field in a second dielectric given a 2 dielectric system

    I tried approaching this by finding the tangential and normal electric fields. Is this the correct approach? I've attached a drawing of the surface provided. ##\oint_S E \cdot dl=0## ##E_{tan1}\Delta x-E_{tan2}\Delta x=0## We know that ##E_{tan1}=E_{tan2} Next, we can find the normal...
  36. Athenian

    Finding the Monopole and Multipole Moments of the Electric Potential

    My first attempt revolved mostly around the solution method shown in this "site" or PowerPoint: http://physics.gmu.edu/~joe/PHYS685/Topic4.pdf . However, after studying the content and writing down my answer for the monopole moment as equal to ##\sqrt{\frac{1}{4 \pi}} \rho##, I found out the...
  37. P

    Position for maximum electric field between two wires

    For the first part, since $$ E(r) \propto \frac{1}{r} \hat{r}$$ by the principle of superposition the maximal electric field should be halfway in between the two wires. Then I'm not sure how to go about the second part of the question. I understand that the total potential due to the two wires...
  38. M

    Find the electric field intensity from an infinite line charge

    what I've done so far? -i've determined the vector between the point (4, 0, 0) and the point P. (4, 6, 8) - (4, 0, 0) (0, 6, 8) -The norm of this vector is the radial distance of the line to point P (the value of “ρ” in the formula) √(0^2 + 6^2 + 8^2) = 10 -> ρ = 10 -and its unit vector is...
  39. wcjy

    Electric field problem using Gauss' law: Point charge moving near a line charge

    F = qE ma = (2*10^-6) * (λ / (2pi*r*ε0) ) ma = (2*10^-6) * (4*10^-6 / (2pi*4*ε0) ) => I am not certain what to put for r ( But I sub in 4 because dist is 4) a = ( (2*10^-6) * (4*10^-6 / (2pi*4*ε0) ) )/ 0.1 a = 0.35950 v^2 = U^2 + 2 a s v = 0 u^2 = -2 a s => Can't sqrt negative so...
  40. C

    Help finding the equilibrium position of an electric field

    I seem completely lost at this. I barely know where to begin. I know that the forces will sum to 0 but the vectoral nature of the question is really confusing me. Best I have is that the distance between e and q2 has to be sqrt(2) times the distance between e and q1. I don't know where to go...
  41. E

    Net electric force of multiple charged particles in 3-d space

    I draw the graph like this: For (b), I divided each force vector to e from p1 and p2 as x and y parts. I computed them and got Fx=-4.608*10^(-15)N Fy=-2.52*10^(-15)N However, I am not sure whether I did it correctly or not... I appreciate every help from all of you! Thank you!
  42. Z

    Electric Field Divergence of Monochromatic Plane Wave: Why is it Zero?

    Why is the divergence of an amplitude of an electric field of a monochromatic plane wave zero?
  43. F

    Efficiency of charging new and old Li-ion batteries in electric cars

    An electric car has, say, a 50 kWhr battery. 1. How much electricity, in kWhr, is needed to add 1 kWhr of stored electricity to the battery? 2. After several years, the battery capacity has, say, fallen to 25 kWhr. How much electricity, in kWhr, is now needed to add 1 kWhr of stored...
  44. Sj4600

    Electric Potential Energy Question: Electron and Proton accelerating between charged plates

    Ve=0m/s Vp= 0m/s Qe/Qp= 1.60E-19 Me=9.11E-31 Mp-1.67E-27 Ive pretty much gathered all of the equations I think I need to solve the problem. I just am stuck. The last step I realize that the forces would be equal to each other so I have mp x ap = me x ae but then when I try to solve for the...
  45. bln1230

    Help me find the electric field vector

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  46. B

    Electric Potential inside an insulating sphere

    I used the potential at the surface of the sphere for my reference point for computing the potential at a point r < R in the sphere. The potential at the surface of the sphere is ## V(R) = k \frac {Q} {R} ##. To find the potential inside the sphere, I used the Electric field inside of an...
  47. J

    Finding equations for electric field lines

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  48. P

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    Hi, I'm dealing with a more or less trivial question. Let's have a look on two situations. Consider a (negative) charged metal plate. If the plate is infinit in size it will produce a perfekt homogeneous electric field. If we now place a second plate parallel to the first one the electric...
  49. archaic

    Maximum electric field at the surface of a Van de Graaff generator

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  50. madafo3435

    Electric field due to a flat hollow disk

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