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. R

    Question re electrostatic charge

    Somewhat of a rudimentary question. Not sure it belongs in the QM forum-----2 electrons--one on left----one on right----1 cm apart. A repulsive force exists betw the two. Now a 3rd electron is brought in on left. Will this increase the repulsive force on the electron on the right----or to feel...
  2. R

    Electrostatic interaction energy example (jackson)

    Homework Statement I am trying to follow a derivation in Jackson - Classical ElectrodynamicsHomework Equations In equation 1.58 (2nd/3rd edition) of Jackson - Classical Electrodynamics he says that by using the fact that \mathbf{\rho} \cdot (\mathbf{\rho} +\mathbf{n})/ | \mathbf{\rho +n|}^{3}...
  3. O

    Where do the electrostatic energy go?

    Fun Fly Stick is a toy to generate electrostatic energy, please see an attached image. I am insulated from the floor and the stick is touching the metal wall, the longer I operate it, should my body get more negative charges or less? " ... An electron has a mass that is...
  4. M

    Determining if a field is electrostatic or not

    If i have an arbitrary vector field, say F = constant / (x^2 + y^2 +z^2) I want to determine if it is electrostatic or not. For this I am thinking I should first determine if it is a conservative field, but not 100% sure, any guidance would be appreciated :) mitch
  5. O

    Possible to generate Electrostatic energy using battery?

    Battery has positive and negative charges, will it be possible to generate electrostatic energy to my body by touching either sides of battery? Thanks in advance for any suggestions
  6. N

    Electrostatic forces/fields

    Homework Statement An unknown charge and a charge of 60 nC are 2.0m apart. The electric field strength is zero at a point 0.80m from the unknown charge on a line connecting the two charges. Find the magnitutde of the unknown charge. Homework Equations q=F/E F=kq1q1/r^2 E=kq/r^2...
  7. O

    Electrostatic energy on my cat?

    When I play with my cat, there is some electrostatic energy generating between my hands and cat's fur, does anyone have any suggestions whether my body get positive charges after playing with my cat or negative charges? Thanks in advance for any suggestions
  8. C

    Speed of propogation of electrostatic field

    (Not sure if this should go in SR/GR forum) I watched a Susskind lecture last week in which he was discussing the fundamental law of charge conservation. He used the example of an electrostatic field surrounding a point charge, and stated that, were we able to suddenly make the charge...
  9. F

    Are these two calculations of electrostatic force correct?

    I was watching a show the other night about the Large Hadron Collider, and I got to wondering how much force it would take to push two uranium nuclei right up against each other. I figured it would be on the order of a thousandth, maybe a millionth of a pound, which seems like a lot, considering...
  10. Z

    Express electrostatic potential as a Fourier integral

    Homework Statement The charge distribution of an atomic nucleus is modeled by the Gaussian distribution: p(r) = A exp(-r2/a2) Obtain the Fourier transform of p(r), and use the result to obtin an expression for the potential as a Fourier integral. Homework Equations Fourier transform and...
  11. D

    Electrostatic force between point charge and dielectric ball.

    At a certain distance from a point charge q there is small, dielectric ball. How would change the value of electrostatic force acting on the ball, if the value of a point charge would be doubled? According to F=k[(q1*q1)/r^2] there would be no force on the dielectric ball, because his resultant...
  12. T

    Why does the supply go past pull-downs but electrostatic voltage through pull-down?

    When you use a pull-down resistor (resistor to ground) between a switch and a gate to prevent floating, why does the supply go past the pull-down but electrostatic voltage through the pull-down? Shouldn't it just go through whichever one has less resistance? Is there some kind of 'bandwidth...
  13. M

    Electric field in an electrostatic precipitator.

    Homework Statement Electrostatic precipitators use electric forces to remove pollutant particles from smoke, in particular in the smokestacks of coal-burning power plants. One form of precipitator consists of a vertical, hollow, metal cylinder with a thin wire, insulated from the cylinder...
  14. A

    Perturbation of a uniform electrostatic field by a dielectric cube

    Hi, Is there any way to analytically calculate the perturbation of a uniform electrostatic field by a dielectric cube. I know a solution exists for dielectric spheres but I haven't been able to come across the solution, when dealing with a cube. Ohh.. and I'm assuming the simplest case...
  15. R

    ElectroStatic Equilibrium problem

    Homework Statement particle 1 of charge q1 (at origin) and particle 2 of charge q2 = 3q1, are held at separation L on an x axis. If particle 3 of unknown charge q3 is to be located such that the net electrostatic force on it from particles 1 and 2 is zero, what must be the (a) x and (b) y...
  16. P

    Electrostatic Force between the sodium ion and the chloride ion.

    In solid sodium chloride (table salt), chloride ions have one more electron than they have protons, and sodium ions have one more proton than they have electrons. These ions are separated at about 0.28 nm. Calculate the electrostatic force between the sodium ion and the chloride ion. What I...
  17. B

    Electrostatic Force position

    Homework Statement An electric point charge of Q1 = 5.23 nC is placed at the origin of the real axis. Another point charge of Q2 = 1.89 nC is placed at a position of p = 2.63 m on the real axis. At which position can a third point charge of q = -2.62 nC be placed so that the net...
  18. T

    What is electrostatic noise and how does it affect analog and digital signals?

    I started an electrical engineering degree this semester. My book says that electrostatic noise meaningfully affects analog but not digital. But it does not say what electrostatic noise is, and neither Google nor Wikipedia readily yield an answer to this question: What is electrostatic noise?
  19. jfy4

    Express electrostatic energy in terms of both charges

    Homework Statement For two concentric conducting spheres (radius a and b, b>a) that form a capacitor with charge q on the inner sphere and -q on the outer sphere, express the electrostatic energy in terms of q and -q and the potential difference between them.Homework Equations Gauss's Law, the...
  20. L

    Electrostatic force and magnitude problem

    In the figure, the net electrostatic force on Q1 is zero. If Q1 = +4.99 nC, determine the magnitude of Qo. Qo = (r0/r1)^2 * abs(q)*2cos theta The figure is attached, please help, I'm so lost with physics II
  21. L

    Induced charges and electrostatic potential

    There is one point I am unclear upon in terms of indued charges. If a charge is induced by another charge, will the potential from the induced charge have an effect on the inducing charge. It seems that if it were the case you would be getting (increasing) energy from nothing, however if it...
  22. C

    Electrostatic Force and Coulomb's Law

    Homework Statement A charge of 6.00 x 10-9C and a charge of -3.00 x 10-9C are separated by a distance of 60.0 cm. Find the position at which a third charge, of 12.0 x 10-9C, can be placed so that the net electrostatic force on it is zero. Homework Equations Coulomb's Law The...
  23. C

    Coulomb's Law and Electrostatic Forces Problem

    Homework Statement Three charges are arranged as shown in the picture I attached. Find the magnitude and direction of the electrostatic force on the charge at the origin.Homework Equations I know that Coulomb's Law must be applied.The Attempt at a Solution I've drawn a force diagram with FCB...
  24. A

    Equillibrium of electrostatic forces of 2 charges on a 3rd

    Homework Statement Two particles lie on the x axis. The first particle is at the origin with a charge of +1.6uC and the other has a charge of -3.1uC and is +10.5cm away. If particle 3 of unknown charge q3 is to be located such that the net electrostatic force on it from particles 1 and 2...
  25. B

    What does the energy of an electrostatic field mean?

    Hello everyone. So that is my question: What does the energy of an electrostatic field mean? A more detailed description of my background or understanding will help you to provide an answer: The process to deduce such a thing is usually calculate the work done in order to bring charge...
  26. B

    Electric field in electrostatic situation

    Homework Statement Two particles with positive charges q1 and q2 are separated by a distance s. Along the line connecting the two charges, at what distance from the charge q1 is the total electric field from the two charges zero? Homework Equations E = kq/r2 where k = 1/(4 x pi x...
  27. T

    Electrostatic Potential Concept

    My textbook says that Electrostatic potential is the work done on a unit charge to bring it from infinity to a point from a given charge without acceleration, against the electric field presend due to the given charge. So, as it says that there will be no acceleration, does it imply that...
  28. P

    Integral/ electrostatic difficulty

    I have a little trouble solving Electrostatic problems (at undergraduate level) that involve volume or surface integrals when there are normal vectors involved, and one must (normally) dot this with a vector field (such as electric field) when one cannot use Gauss's law. one such example I...
  29. P

    Electrostatic potential of two spheres

    Homework Statement Two identical conducting spheres, with a radius of 15.0 cm, are separated by a distance of 10 m. What is the charge in each sphere, if the potential of one sphere is +1500 V, and the potential of the other one is -1500 V? Which assumptions did you make? Homework Equations...
  30. M

    Different descriptions of electrostatic energy

    This is actually a question pertaining to a paper I'm trying to understand (PRB 73, 115407 (2006)), but I decided to put it here just to be safe. Homework Statement The paper I'm reading involves starting with an electrostatic energy contribution, and rewriting it with a green's function...
  31. hanley93

    About Electrostatic Forces on Parallel Plate Capacitor

    I've been thinking about this for a while, and I think people of PF will be able to answer it haha In parallel plate capacitor, we charge the capacitor by connecting a power supply/battery. Then, after few minutes, the capacitor is fully charged with different signs, + and -. With that...
  32. L

    A question about Volume charge density and electrostatic equilibrium

    The concept of volume charge density is an even distribution of charge over a three dimensional area. C/m^3. However, the concept of electrostatic equilibrium says that all of a conductors charge lies on the surface of the conductor. The existence of one seems, to me at least, to render the...
  33. Y

    Electrostatic force between sodium ion and a chloride ion

    Homework Statement In solid sodium chloride (table salt), chloride ions have one more electron than they have protons, and sodium ions have one more proton than they have electrons. These ions are separated by about 0.28 nm. Calculate the electrostatic force between a sodium ion and a chloride...
  34. G

    Can Electrostatics Cause Problems?

  35. D

    Electrostatic question with three circular disks.

    Homework Statement Two discs are each charged +q. A third metal disc of radius R∗ > 5 cm is carefully inserted between the two discs; the third disc is neutral and is suspended by an electrically insulating thread. The three discs are all parallel to each other and their centers lie along the...
  36. J

    Electrostatic increase of particle mass

    I understand that the electrostatic field around a charged particle contributes to its mass. It is as though there is a cloud of mass/energy centred on the charged particle that travels with it contributing to its inertia. I have found that the mass/energy of this cloud can be enhanced by...
  37. O

    Electrostatic force between to spheres

    given to solid half charged sphere Insulators. In which state the mutual net force is bigger: A/B/the same
  38. P

    Electrostatic force between 2 distant parallel plates

    Homework Statement The problem is: If you have 2 rectangular plates 1cmx10cm each, which means that the area is A=10cm2=10-3m2for each plate; every plate holds a Constant positive charge of Q=+2x10-6C each; these plates are separated by a distance d=1cm=10-2m What is the electrostatic...
  39. P

    Electrostatic Force: Finding mA:mB Ratio

    I have some problems withe this question: Two positively charged particles A and B of masses of mA and mB respectively are suspended by two insulating threads of the same length from O. Due to the electrostatic repulsive force between A and B, threads from AO and BO make 30 degrees and 60...
  40. J

    What is the influence of electrostatic on water ?

    what is the influence of electrostatic on water ?
  41. 3

    How Is Equilibrium Distance Calculated Between Charged Spheres?

    At the two ends of a pole there are two + charged spheres.One has a charge n times that of the other (nq and q). Along this pole, of length we will call d, there is another charged sphere which is located at an equilibrium position we will call x units away from the first sphere. My task is to...
  42. T

    How Do Protons Behave in a Particle Accelerator?

    Homework Statement Protons are bring accelerated through a potiential difference of 5.00 x 10^3 V in the gun of a particle accelerator. They must pass between two parallel deflecting plates that are 6.0 x 10^-2 m long and 2.0 x 10^-2 m apart with a potiential difference between them of 1.50...
  43. R

    Electrostatic Forces on Three Hypothetical Parallel Planes

    Say there is are three hypothetical infinite parallel planes with charges on it. So let's imagine the three planes from left to right, or planes one, two and three. Plane-three is fixed to the reference frame. Plane-one and plane-two have a fixed separation distance between each other, but...
  44. D

    Parallel capacitor, electrostatic energy

    Homework Statement if the separation between the plates of an isolated charged parallel-capactior is increased, why does the stored electrostatic energy increase? Homework Equations C=eA/d e= permitivity of space The Attempt at a Solution i do not know the equation of...
  45. F

    I just don't understand this Spring - ElectroStatic problem

    Homework Statement http://img832.imageshack.us/img832/17/unledqp.png Above is the problem and the solutions The Attempt at a Solution Now I really have problems with how the factors of the radius is in there. I did it differently This is how I did it \sum W_{ab} = \Delta K \int...
  46. P

    Can we have electrostatic levitation using capacitor type plates?

    Hi all, I am in the process of developing a science project. That is when I came across different types of levitation including electrostatic levitation. Maglev trains are a good example of magnetic levitation. We know that like charges repel each other. Its on the last sentence that I...
  47. R

    Final velocity of 2 spheres attracted by gravity and electrostatic charge

    Homework Statement Two insulating spheres having radii 0.22 cm and 0.42 cm, masses 0.16 kg and 0.47 kg, and charges −4 μC and 5 μC are released from rest when their centers are separated by 1 m. How fast is the smaller sphere moving when they collide? Answer in units of m/s...
  48. N

    Electrostatic Potential of a Charged Metallic Shell

    Homework Statement Given a charged metallic spherical shell of radius a=2.75cm, with a potential of 2.5kV a distance of r=6.0cm from the center of the shell, what is the charge on the shell? Calculate the potential on the surface of the shell.Homework Equations V=kQ/rThe Attempt at a Solution...
  49. J

    Question about electrostatic equilibrium?

    Two fixed charges, 3.0 uC and 5.0 uC, are 0.40 m apart. The 3.0 uC is to the left of the 5.0 uC charge. Where should a third charge of 2.0 uC be placed to put the system of three charges in electrostatic equilibrium? The answer should be measured with respect to the 5.0 uC charge. What...
  50. V

    Electrostatic potential and capacitance

    Homework Statement C120 uF C2=40uF C3= 50uF if no capacitor has the capacity to bear more than 50V then maximum potential difference between the two ends is Homework Equations Q=CV The Attempt at a Solution i tried by calculating the Ceq then putting it in the equation finding...
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