What is Electrostatic: Definition and 879 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. M

    Electrostatic Potential Energy of an ion

    Working from Krane's Modern Physics 11.5 Calculate the first 3 contributions to the electrostatic potential energy of an ion in the CsCl lattice. I believe the formula I'm supposed to use is U_{c}\,=\,-\alpha\frac{e^{2}}{4\pi\epsilon_{0}R} Just from looking in the chapter I can...
  2. M

    Voltage due to electrostatic induction

    Hello All, I have an arcane curiosity that cannot be answered anywhere I look (including Griffiths' intro electrodynamics book and the internet). This question seems so simple but I may just be over-thinking it. If there are two square, parallel, finite, conducting plates and a point...
  3. M

    Insulator and conductor with electrostatic problems

    I was wondering, what is the distinction made with problems involving either conductors or insulators with electrostatic problems. Is it that the electric field in an insulator doesn't have to be zero, whereas the electric field in a conductor is always 0?
  4. M

    Plate conductor in electrostatic equilibrium

    Homework Statement A thin, square, conducting plate 50.0 cm on a side lies in the xy plane. A total charge of 4.00 x 10-8 C is placed on the plate. Find (a) the charge density on each face of the plate, (b) the electric field just above the plate, and (c) the electric field just below the...
  5. P

    Variations of electrostatic potential energy

    Hello, (this isn't homework but I thought it wasn't worthy of the main forums) I'm looking to clarify some thoughts about the various forms of electrostatic potential energy. As I understand, the expression \displaystyle \frac{\epsilon_{o}}{2} \int \textbf{E} \cdot \textbf{E} \; dV over all...
  6. L

    Simple electrostatic fields questions

    Imagine nine vertical and parallel lines drawn side by side. They represent infinite planes of uniform voltage. The first line has 0 V. The 2nd line has 1 V. The 3rd has 2 V and so on, with the 9th line having 8 V. The distance between each line is 1 cm, which is 0.01 meter. There is an...
  7. D

    Electrostatic Force of a Triangle

    Homework Statement Suppose that the magnitude of the net electrostatic force exerted on the point charge q2 in the figure is 0.65 N . (Figure 1) http://imgur.com/4lZliPq Find the distance D. q1 = 2.1 micro C q2 = 6.3 micro C q3 = -.89 micro C Homework Equations F = k |q1|...
  8. F

    Hessian matrix of potential energy in electrostatic system

    Hi everyone: I am rookie in classical physics and first-time PF user so please forgive me if I am making mistakes here. My current project needs some guidance from physics and I am describing the problem, my understanding and question as below. I have an independent electrostatic system...
  9. Saxby

    Differentiating electrostatic force

    Homework Statement Obtain an expression for the potiential energy between to particles in an ionic bond at radius r0 Homework Equations Coloumb's laws: F = (-k * q1 * q2)/r-1The Attempt at a Solution I think that if i do U = r0∫0 F(r)dr = [k * q1 * q2 * r-1]r00 = k * q1 * q2 * r0-1, Then that's...
  10. A

    Electrostatic potential at a point outside a sphere

    A conducting spherical shell of radius 11.0 cm is charged to a potential of 5.00*10^4 V. What is the value of the electrostatic potential 5.0 cm outside the surface of the sphere? V=(1/[4*pi*(epsilon naught)])*(Q/r) <-- outside of the shell V=(1/[4*pi*(epsilon naught)])*(3Q/2R) <-- inside...
  11. S

    Electrostatic charges in ionic compounds

    From this link: http://www.chemguide.co.uk/atoms/structures/ionicstruct.html it explains why NaCl has a 6:6 coordinated structure and not an 8:8 coordinated structure. However, i don't really understand their explanation "Now imagine what would happen if you replaced the caesium ion with the...
  12. S

    Electrostatic force on a parallel plate

    I'm tasked to find the force one parallel plate exert on the other plate in a capacitor. somehow the force isn't just F=qE, where E=Q/2εA What am I missing here?
  13. M

    Questions about electrostatic charge

    Can one transmit electrons to create an electrostatic charge through electrostatic induction? Can one use a gas to create an electrostatic charge in an item by moving the air next to it? If either of these are true, would it then be possible to create an effecient (I.E. one without...
  14. B

    Finding Electrostatic Force

    Homework Statement A 8.15 nC charge is located 1.95 m from a 4.18 nC point charge. (a) Find the magnitude of the electrostatic force that one charge exerts on the other. N (b) Is the force attractive or repulsive? Homework Equations The Attempt at a Solution Is there really a...
  15. G

    Chemistry Intramolecular, intermolecular, electrostatic forces

    I'm getting a bit confused as to what each force refers to. Correct me if I am wrong, Intermolecular forces (also referred to as electrostatic forces), are forces that exist between molecules. These forces can very in strength, strongest in liquids, relatively weaker in liquids, and almost...
  16. C

    Electrodynamics: Electrostatic field potencial in Cartesian coordinates

    Homework Statement It's given that absolute permitivity is a coordinate function: ε (x, y, z) = Asin(x)cos(y), where A=const Homework Equations We need to find an electrostatic field potential function \varphi in Cartesian coordinate system. The Attempt at a Solution I tired to solve, but...
  17. V

    Electrostatic energy per e- for an alkali metal

    I'm trying to think about what it is I should be considering before I start throwing up some maths. I'm thinking to assume that the positively charged core is a point charge +e and the electron is uniformly distributed over a sphere of radius Rs. The self energy of the electron...
  18. D

    Comparing Magnetic & Electrostatic Experiments

    1. Similarities and differences between magnetic and electrostatic experiments can include: 2. What are there factors individually and then decifer 3. Similar- both have positive 'and/or' negative charges. Differences- electrostatic must involve an imbalance of positive or...
  19. M

    Distance from +4μC to Zero Potential: 24mm

    Homework Statement The diagram shows two charges, +4 μC and –16 μC, 120 mm apart. What is the distance from the +4 μC charge to the point between the two charges where the resultant electric potential is zero? A 24mm B 40mm C 80mm D 96mm Homework Equations potential equation...
  20. O

    What is different between electrostatic voltage and circuit voltage?

    I'm confused about this because voltage or potential difference is defined as work done by an external source in moving a unit charge from one point to another in an electric field. However, in circuit analysis things seem to be different because we measure voltage from V=IR. I want to...
  21. P

    Electrostatic forces between multiple particles

    So I was reading my textbook and it says that we are given a situation where two particles of the same charge are separated by the distance 0.0200m. Another particle of the opposite charge is then placed in between the other two particles, 3/4 the distance mentioned away from one and thus 1/4...
  22. W

    Find an expression for the electrostatic energy of this charge distribution.

    Homework Statement Homework Equations work = kqqq/(distance) The Attempt at a Solution http://i33.photobucket.com/albums/d86/warnexus/electrodiag.jpg
  23. S

    Electrostatic fields in vacuum

    Homework Statement An atom H has a charge +q (=proton) and -q(=electron). q = 1,6.10^-19. The electron is circeling around the proton at r distance r = 0,53.10^-10m. What is the force as a result of the electrostatic interaction between the proton and electron Homework Equations...
  24. G

    Can these diagrams describe an electrostatic field in a charge free space

    Homework Statement Determine if the following diagrams may describe an electrostatic field in a charge-free space. The rectangles are the spaces under consideration. In the first four diagrams there are field lines while in the last two there are equipotential lines Homework Equations...
  25. B

    Starting an electrostatic cylinder problem

    Homework Statement http://img842.imageshack.us/img842/2816/unavngivettz.png My problem is that I'm confused about a hint I was given in this problem. I usually use the law of cosine to find the length of \vec{r}-\vec{r'} in sphere problems. But the hint I have says that I should make it...
  26. D

    Electron trapping by electrostatic force

    I'm curious about electron trapping by electrostatic force. A simple scenario can be ... A perforated, conductive, hollow sphere in a vacuum, connected to a negative high voltage source. I want to calculate how much electrons it can hold (total charge of it). The relation between sphere voltage...
  27. D

    Electrostatic Printer and two plate capacitors deflecting charged ink droplets

    Homework Statement One type of ink-jet printer, called an electrostatic ink-jet printer, forms letters by using deflecting electrodes to steer charged ink drops up and down vertically as the ink jet sweeps horizontally across the page. The ink jet forms 30-μm-diameter drops of ink, charged...
  28. F

    Electrostatic equilibrium (Sphere with cavity)

    Homework Statement Consider a sphere conductor with a inner concentric sphere cavity. The radius of the inside and outside of sphere are 10 cm and 20 cm. The electric field in a point P, along the outer surface has a intensity of 450 N/C and it is directed out of the surface. When a particle...
  29. F

    Electrostatic energy of spherical shell.

    Homework Statement Determine the electrostatic energy, W, of a spherical shell of radius R with total charge q, uniformly distributed. Compute it with the following methods: a) Calculate the potential V in spherical shell and calculate the energy with the equation: W = (1/2) * ∫σVda...
  30. S

    Electrostatic Separation of Variables in a Square Pipe

    Homework Statement I'm solving a problem where a conducting pipe with a square cross section is being analyzed to find the potential everywhere in space. The pipe lays along the z-axis, so we're really concerned with the x-y plane. My issue isn't so much the general solution via separation...
  31. E

    Electrostatic potential energy of a nonconducting sphere

    Homework Statement Determine the total electrostatic potential energy of a nonconducting sphere of radius r0 carrying a total charge Q distributed uniformly throughout its volume. Express your answer in terms of the variables Q, r0, and appropriate constants. Homework Equations V = kQ/r...
  32. D

    Verifying that electrostatic potential satisfies Poisson's equation

    i'm trying to understand how the electrosatic potential expressed as an integral satisfies poisson's equation. i know that i have to take the laplacian of both sides of (Eq 1.17) page 35 in Jackson. i understood how jackson took the laplacian of \frac{1}{\sqrt{r^2 + a^2}} but after Eq 1.30...
  33. S

    How Is the Electric Field Calculated at the Third Vertex of a Triangle?

    Homework Statement What is the electric field at the third vertex. http://tinypic.com/r/350toif/6 edit- not working actual link works = http://tinypic.com/r/350toif/6 Homework Equations E=kq/r^2 The Attempt at a Solution E1= (labeled on the diagram) = (8.99*10^9)(4)/(.02)^2 =...
  34. M

    Compute electrostatic field

    hello! "there is a high computational expense associated with calculating the local electrostatic field [in molecular modeling and simulation]" why? what is exactly the problem? thanks!
  35. J

    Electrostatic energy of two opposite charges in water and in a vacuum

    Homework Statement Compare the electrostatic energy of two opposite charges e and -e, a distance 7 angstroms apart in water at room temperature and that in vacuum (express the energy in terms of Bjerrum length) Homework Equations E = 1/(4(p\pi\epsilonD)*(-e^2)/r^2 ? The Attempt at a...
  36. P

    Electrostatic force using vectors

    Homework Statement Charge A is +2C and is located at <4,0,0> Charge B is +12.5C and is located at <0,-3,0> What is the the Force(AonB) What is the magnitude of F(AonB) Homework Equations F = (k)(Qa)(Qb)/(r^2) (r^) For reference the answers are < -0.8k, 0.6k, 0 > N (F...
  37. tomwilliam2

    Electrostatic potential using method of images

    Homework Statement There is a charge q, at a distance d from an infinite conducting plane (z=0). Determine the electrostatic potential drop between the z=0 and z=d. Homework Equations Ohm's Law DeltaV=-integral (E.dl) The Attempt at a Solution I know how to do this problem...
  38. D

    Electrostatic Energy of Sphere in Shell

    Homework Statement Compute, in the following two ways, the electrostatic energy W of the uniformly charged solid sphere of radius a (charge density \rho) that is surrounded concentrically by a uniformly charged thin spherical shell of radius b (surface charge density \sigma), where the...
  39. J

    How Can I Create an Electrostatic Adhesion Gripper for My Robotics Project?

    G'day, I've got a little robotics project that I'm working on, and I've been thinking of adding a little electro-static adhesion gripper to it. This gripper will used to pick up an aluminium softdrink can (300ml I think), which weighs 100gm. At the moment, I don't care what it can pick up...
  40. S

    Magnitude of the electrostatic force

    Hello, Any help woould be wonderful! Identical point charges Q are placed at each of the four corners of a rectangle measuring 2.35 m by 3.05 m. If Q = 26.9 μC, what is the magnitude of the electrostatic force on anyone of the charges? i don't even know where to start... HELP!
  41. M

    Electrostatic interaction

    hello! which equation descripts the electrostatic interaction between two non-point (ie. that have dimensions) charged particles? thanks!
  42. Demon117

    Electrostatic Potential over all space

    If I have a sphere with radius R which has a charge distribution given by \rho(r)=\frac{5Q}{\pi R^{5}}r(r-R) and \rho = 0 at r bigger or equal to R, how do I find the electrostatic potential of this overall space? There is a charge Q, in addition, at the origin. My original thought...
  43. W

    Electrostatic Induction and Spray Painting

    Hi, What is the charge on a droplet of paint? Im trying to understand what's going on in electrostatic spray painting - specifically at the spray nozzle (this could also be crop spraying too) My understanding so far is that a paint supply is fed into a grounded nozzle. An electrode...
  44. J

    Derive Electrostatic Force from Coulomb's Law.

    Homework Statement I should derive \vec{F_{q}} = \frac{-q'^{2}}{4∏ \epsilon_{0}} \frac{r'/a}{(r'^{2} - a^{2})} \hat{r} from \vec{F_{q''q'}} = k\frac{q' q''}{\left|\vec{x'} - \vec{x''}\right|^{2}} Homework Equations The Attempt at a Solution I know that q'' = -q'...
  45. J

    Use Green's Reciprocation Theorem to show the G.S to the Electrostatic Potential

    Homework Statement Use Green's Reciprocation Theorem to show the G.S to the Electrostatic PotentialHomework Equations Green's Reciprocation Theorem \int_{v} \rho^{'} \Phi d^{3}x + \int_{s} \sigma^{'} \Phi da = \int_{v} \rho \Phi^{'} d^{3}x + \int_{s} \sigma \Phi^{'} da The...
  46. J

    Electrostatic Field/Magnetic Fields

    There is an arbitrary vector A=A[R](R,θ,∅)R(phasor) + A[θ](R,θ,∅)θ(phasor) + A[∅](R,θ,∅)∅(phasor). What relationship exists between the three functions A[R], A[θ], and A[∅] if this vector is either: A: Electrostatic Field B: Magnetic field I really have no...
  47. A

    Choose the Right Electrostatic Filter: Criteria to Consider

    What are the criteria for choosing an elctrostatic filter?
  48. B

    Net Electrostatic Force of 4 Charges at a Regular Triangle Pyramid

    Homework Statement 4 identical charges each equal to Q are placed at the 4 vertices of a regular triangular pyramid of each side equal to 'a'. Find the net electrostatic force on anyone charge. Homework Equations F = kQ^2/a^2 The Attempt at a Solution find the force due to each...
  49. B

    Electrostatic potential with floating metals:computation and measurement

    Hi all, I am considering the situation illustrated in the schematic below. A surface density of permanent charges σ is embedded into a dielectric (with relative permittivity εr) itself sandwiched between two electrically floating metallic plate. We have also L>>t1 and L>>t2. My first goal is...
  50. R

    Mediator of electrostatic repulsion

    Is the repulsive force between 2 electrons---(as in an electrostatic situation)---mediated by a photon----?------R Rosenthal
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