What is Electrostatics: Definition and 675 Discussions

Electrostatics is a branch of physics that studies electric charges at rest.
Since classical physics, it has been known that some materials, such as amber, attract lightweight particles after rubbing. The Greek word for amber, ήλεκτρον, or electron, was thus the source of the word 'electricity'. Electrostatic phenomena arise from the forces that electric charges exert on each other. Such forces are described by Coulomb's law.
Even though electrostatically induced forces seem to be rather weak, some electrostatic forces such as the one between an electron and a proton, that together make up a hydrogen atom, is about 36 orders of magnitude stronger than the gravitational force acting between them.
There are many examples of electrostatic phenomena, from those as simple as the attraction of the plastic wrap to one's hand after it is removed from a package to the apparently spontaneous explosion of grain silos, the damage of electronic components during manufacturing, and photocopier & laser printer operation. Electrostatics involves the buildup of charge on the surface of objects due to contact with other surfaces. Although charge exchange happens whenever any two surfaces contact and separate, the effects of charge exchange are usually only noticed when at least one of the surfaces has a high resistance to electrical flow. This is because the charges that transfer are trapped there for a time long enough for their effects to be observed. These charges then remain on the object until they either bleed off to ground or are quickly neutralized by a discharge: e.g., the familiar phenomenon of a static "shock" is caused by the neutralization of charge built up in the body from contact with insulated surfaces.

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  1. P

    Potential energy due to an external charge and a grounded sphere

    Let us attempt part C first, which is to find the total energy of the entire system. I can definitely find an expression for the force, as given by Coulomb's Law. However, why should I integrate this force from infinity to d, where d is the distance of the external charge to the centre of the...
  2. P

    Force needed to hold together a capacitor

    I have 2 methods, which give 2 different solutions: Let sigma = charge per unit area Let plate 1 be the left plate, plate 2 = right plate. Method 1: Because they are insulating, consider the electric field at 3 regions; region 1 to the left of plate 1, region 2 between the plates, and region 3...
  3. iVenky

    Dielectric and Attraction Between Oppositely Charged Plates

    I am not able to intuitively understand the reasoning behind why the presence of dielectric between oppositely charged plates, let's say, reduces the force of attraction between the plates. I understand to some extent that electric field lines prefer to flow through dielectric (or insulator)...
  4. llha

    E-Field immediately outside a charged conductor

    Griffith's says this, and I'm not exactly sure why... If you had a solid, spherical, and externally induced conductor... Does this mean that IMMEDIATELY outside, when you're infinitesimally close to the surface, E looks like this? If you surround the entire conductor with a Gaussian surface...
  5. R

    Electrostatic Induction in Metals vs Insulators

    If we have a small dielectric sphere and a point charge, they will experience an attractive force due to electrostatic induction. (From the elongation/rotation of charges bound to individual atoms). Likewise, if we have a small metallic sphere and a point charge, they will experience an...
  6. namo99

    A charged particle entering a magnetic field -- find the position

  7. sroot

    Help with electrostatics problem (spherical shell charge distribution)

    According to my professor, the solution in this book (pages 20-21) for item (ii) is wrong: https://www.u-cursos.cl/usuario/75468645ed16a71af6da3ffd813d47f5/mi_blog/r/Problems_and_Solutions_on_Electromagnetism.pdf
  8. B

    Understanding the electric field of a sphere with a hole

    Here's an image. O and O' are the respective centers, a is the distance between them, r is the distance from the center of the sphere to P, and r' = r - a, the distance from O' to P. The approach (which I don't understnad) given is to use Gauss' Law and superposition, so that we calculate the...
  9. P

    Electrostatics - electric potential and field strength (dielectric)

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  10. patric44

    Finding the magnetic field B given the vector potential A ?

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  11. P

    Electrostatics - two charged balls

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  12. AHSAN MUJTABA

    Electrostatics problem related to polarization and a cylindrical dielectric

    I understand that the above eqs would be used but I clearly don't know how to use them. I am a bit confussed.
  13. P

    Electrostatics: Calculate the Electric Field near a Charged Ring

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  14. B

    Redistribution of Pre-Charged Capacitors

    I first calculated the charge each capacitor has after its directly charged by the 36 V battery. ##Q_1 = C_1 * V = (2 \mu F) * 36 V = 72 \mu C## ##Q_2 = C_2 * V = (5 \mu F) * 36 V = 180 \mu C## ##Q_3 = C_3 * V = (7 \mu F) * 36 V = 252 \mu C## Then these capacitors connect in series, so I...
  15. S

    Electrostatics problem with charged particles accelerating

  16. AHSAN MUJTABA

    Electrostatics potential calculation for a uniformly charged square

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  17. preachingpirate24

    Electric Field inside the material of a hollow conducting sphere

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  18. Amitkumarr

    To find induced charges on the edges of a right pyramid

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  19. A

    Are electric circuits considered as electrostatics or electrodynamics?

    Thanks in advance!
  20. B

    I Schiff moment in classical electrostatics

    Hello! I just found out about the Schiff moment. This is the paper where I encountered it, equations 3 and 4. The paper covers other things, too, that are not related to my question. The main question I have is that, it seems like the derivation from equation 1 to 4 is purely classical (one can...
  21. Flaming Physicist

    Electric force between two equal parallel rings of charge

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  22. Zeymare

    Electrostatics and capacitors

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  23. B

    Max surface charge of a conductive plate

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  24. O

    Higher dimensional FTC in electrostatics: Mathematically rigorous or not?

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  25. I

    Electrostatics question (Work and Potential)

    a) From X -Y. The work done on the positive charge is negative as the displacement is in the negative y-direction i.e. It is a positive charge moving in parallel to a negative E-field: W= F*(-s) = (+)(-) = - b) Y-Z. The work done is 0. The E-field in the x-direction is 0 as they cancel due to...
  26. T

    In electrostatics, what is meant by positive charges?

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  27. R

    Exploring the Physics of Attraction & Repulsion: A Feynman Lecture

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  28. R

    A doubt on Electrostatics -- An electrified rod attracting light objects

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  29. F

    Electric field Difference between Electrostatics and Electrodynamics

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  30. L

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  31. torito_verdejo

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  32. L

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  33. M

    Electrostatics: Understanding this "Work Done" Line Integral Question

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  34. NP04

    What is this constant (regarding electrostatics)

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  35. N

    Studying Self study of Electrostatics Advice needed

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  36. T

    Electrons cannot sense electrostatic force?

    Why there is not voltage or current just for 1ms if I connect a multimeter ground to the negative terminal of a DC power supply or charged capacitor? Why electrons in measure lead and DMM device cannot sense a bulk of electrons (or lack of it)? I tried with an 5kV DC power supply too. In an...
  37. Z

    The Energy of a Continuous Charge Distribution (Griffiths EM Sect. 2.4.3 3rd ed)

    I'm working through Griffiths EM 3rd ed. in section 2.4.2 (point charge distribution) and 2.4.3 (continuous charge distribution). I understand from the section on point charge distributions that when we add up all the work (excluding the work necessary in creating the charge itself), one clever...
  38. Aryamaan Thakur

    Electric potential at the edge of a thin charged circular plate

    My question might sound stupid to you but please clear my confusions. I'm taking an circular arc like element on the plate. That arc has a radius of 'r' (AB) and the radius is inclined at an angle 'θ' with OA (∠OAB). The area between arc of radius r and r+dr is dA. dA = 2θr.dr The charge on...
  39. Gursimran Singh

    Potential energy of a shell and a disc, both covered uniformly with charge

    Double integration maybe?? I calculated potential due to shell on plate's center but not on other points on it's surface.
  40. ybisno

    Given Electric field, find the charge densities

    Hi. Need help with physics homework. I was able to separate each term and find sigma from the second term and possibly lambda from the first term. Not sure how to approach the third term. (attached attempt at question)
  41. ybisno

    Given Electric Field, Find the charge densities.... (Electrostatics)

    Hi. Need help with physics homework. I was able to separate each term and find sigma from the second term and possibly lambda from the first term. Not sure how to approach the third term. (IMAGE ATTACHED)
  42. Z

    The potential between a cone and a plate

    Homework Statement [/B] There is a conducting cone with angle α placed so that its vertex is normal to an electrically grounded plate, but electrically insulated from the plate and kept at a constant potential V. Find the potential V and the electric field in the region between the cone and the...
  43. PhysicsKT

    Energy density of an electromagnetic field

    The energy density of an electromagnetic field with a linear dielectric is often expressed as . It is also known that energy can be found by . Using the latter, the energy density is found to be , as is well known. If you integrate the latter only over free charge and ignore bound charge, you...
  44. P

    Corollary of the Uniqueness Theorem in Electrostatics

    Following my instructor's notes the statement of the Uniqueness Theorem(s) are as follows "If ##\rho_{inside}## and ##\phi_{boundary}## (OR ##\frac{d \phi_{boundary}}{dn}## ) are known then ##\phi_{inside}## is uniquely determined" A few paragraphs later the notes state "For the field inside...
  45. Aya Elsayed

    I Grounding Process: Neutralizing Negatively Charged Objects

    Let us consider a negatively charged object. We want to neutralize this object, so we touched it by our hands to remove the excess of negative charges by Grounding. Now the question is : Will our body (The Ground) be negatively charged as it gained those negative charges? then why it is called...
  46. A

    What is the electric field of a point charge?

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  47. WhiteWolf98

    Electrostatics - Coulomb's Law

    Homework Statement The magnitude of the electrostatic force between point charges ##q_1 = 26~\mu C## and ##q_2 = 47~\mu C## is initially ##F_1=5.70~N##. The separation distance between the charges, ##r_1## is then changed such that the magnitude of the force is, ##F_2=0.57~N##. (a) What is the...
  48. C

    Exploring Electrostatics with Gauss Theorem

    Having come experimentally to an interesting electrostatic effect, I have returned, aged 47, to my old books in physics. It turns out that my books delight in using Gauss theorem etc. in rather ideal geometrical surface charge distribution, but never gave me the tools to answer to this simple...
  49. Kaan99

    Electrostatic self-force is zero

    Homework Statement Consider a charged body of finite size, (\rho=0 outside a bounded region V). \vec{E} is the electric field produced by the body. Suppose \vec{E} \rightarrow 0 at infinity. Show that the total self-force is zero: \int_V \rho \vec{E} dV = \vec{0}, i.e. the charged body does not...
  50. Alan Lins Alves

    Problem with the Finite Element Method applied to Electrostatics

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