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. J

    Do Electrons gain mass in an electrostatic potential?

    Hi, I have been looking into the phenomenon of Zitterbewegung which is a high frequency oscillatory motion of the electron that is predicted by the Dirac Equation for a free electron. One way of looking at this motion is that it is the interference of plane waves with positive and negative...
  2. P

    Find energy of electrostatic field

    Homework Statement The space between the two concentric spheres is charged by spatial density of charge \rho=\frac{\alpha}{r^2}. The radius of spheres are R_1,R_2. Integral charge is Q. Find energy of electrostatic field. Homework Equations Gauss law \oint_S\vec{E} \cdot...
  3. C

    Electrostatic Potential from a uniform line of charge?

    Homework Statement a) What is the value of an electrostatic potential V, a distance r from a point charge Q? b) A uniform line of charge, of linear charge density (\lambda), extends along the x-axis from x = 0, to x = a. i) By considering the contributions from the infitisimal elements...
  4. H

    Electrostatic homework questions

    Homework Statement 1. a. When a negatively charged object brought close to negatively charged electroscope, the leaf rises more b. When a positive object is brought close to a positively charged electroscope, the leaf becomes closer. Explain the above phenomena 2. Which of the following...
  5. M

    Electrostatic force calculations

    I am trying to calculate the forces in a system with a mix of conductive + dielectric components upon application of an AC potential. Frequencies are low enough that I need not consider magnetic field effects. I can solve equations to obtain the electric field, but at am a loss for force...
  6. J

    Electrostatic force,electric field,electric potential,electric flux

    Cube: 10 cm each side Each q at the corner of the cube is +100 sc. Find: a) magnitude and direction of the electrostatic force at the center of the cube. b) magnitude and direction of the electric field at the center of the cube of tq in place at this pt. c) find the electric...
  7. E

    Understanding the Impact of an Electrostatic Chopper on Beam Characteristics

    Homework Statement Problematic Part of the problem: Consider a negative ion beam of He- ions. The given beam characteristics are the beam energy (E) and the beam current (I). An electrostatic chopper is placed on the beam line, which pulses the DC beam with a pulse width of say t_1...
  8. J

    Magnitude and direction of the electrostatic

    Hello, I'm new in this forum. I hope you can help me in my homework. thank you Homework Statement The given is write in my attachment picture. Homework Equations Find the magnitude and direction of the electrostatic at q4 If they are given equal mass of 1 kg, find the...
  9. A

    Find the ratio of the electrostatic force

    This is the problem: "Determine the ratio of the electrostatic force to the gravitational force between a proton and an electron, FE/FG. Furthermore, note the mass of an electron is 9.109 x 10^-31 kg and the mass of a proton is 1.672x10^-27 kg.G and K are constants." I'm not exactly sure what...
  10. T

    Electrostatic force-Coulombs law

    Homework Statement Hi, I am working on the following question. A 64 µC charge is located 30cm to the left of a 16 µC charge. What is the resultant force on a -12 µC charge positioned exactly 50mm below the 16 µC charge? Homework Equations Coulombs law The Attempt at a...
  11. T

    Does a Positively Charged Ball Attract a Neutral Metal Ball?

    Homework Statement When a positively charged ball is brought near a neutral conductor(a light metal ball), will the metal ball be attracted towards the charged ball? Homework Equations This is electrostatic induction. The Attempt at a Solution Like a charged rod can attract the...
  12. A

    Solving Electrostatic Field & Calculating Capacitance of Microstrip

    Homework Statement I am trying to solve the electrostatic field (2D) for a microstrip laid on a dielectric with a ground plane on the other side. I am also calculating the capacitance of the microstrip by evaluating a closed surface integral to get the charge on the conductors. I am using FDM...
  13. C

    Electrostatic Force curved beam

    Hi, I'm trying to figure out what the electrostatic force between a curved beam (see picture attached) and a standard parallel plate electrode would be. I have an equation for the critical force to induce snapping between the bi-stable states of the beam, but I need to find out one for...
  14. R

    Electrostatic EMERGENCYYY HELP

    Homework Statement An electron beam in the TV tube is steered across the screen by the field between two charged plates. If the electron experiences a force of 3.ox10(to the negative 6th)N, how large is the field between the deflection plates? 2. Homework Statement The custodian dusts...
  15. R

    Electrostatic physics: can someone check my answers?

    1. If the potential difference across the nerve of a frog is 85mV and its resistance is 2.5x10^2 Ω what current will flow through the nerve? Answer: 3.4x10^ -4 2.If all other factors remained the same, what change in resistance would result if the radius of a wire were doubled? Answer...
  16. M

    Direction of electrostatic force and field?

    In a pith-ball electroscope, a ball made of pith, which is a light-weight electrical insulator, is suspended from a hook via a silk thread. When the electroscope is placed in the vicinity of a negatively charged object on the right, the ball moves towards the object. What is the direction of...
  17. R

    Electrostatic potential and velocity

    Homework Statement Point A is at an electrostatic potential of +1V relative to point B in a vacuum. An electron initially at rest at B moves to A. What is its velocity in m/s? Homework Equations E = PE + KE PE= J/q * q KE = 0.5 mv^2 (where v = velocity) The Attempt at a Solution...
  18. Q

    Electrostatic Potential Energy

    Homework Statement How much work is required to exchange the positions of q2 and q3? q2 q3 q1 q1 and q2 are separated by a distance of 4.00 cm and q2 and q3 are separated by a distance of 2.00cm The charge on q1 is 5.00nC, q2 is -5.00nC and q3 is 10.0nC Homework...
  19. S

    Annoying electrostatic question

    so today we had a test about electrostatics. here was the question: a positive charged rod (ungrounded) is to the left of 2 metal conducting spheres, that are initially touching each other. Each metal conducting sphere is hung by a string (which is an insulator). What is the charge of each...
  20. T

    Electrostatic potential in Legendre polynomials

    Homework Statement Two spherical shells of radius ‘a’ and ‘b’ (b>a) are centered about the origin of the axes, and are grounded. A point charge ‘q’ is placed between them at distance R from the origin (a<R<b). Expand the electrostatic potential in Legendre polynomials and find the Green...
  21. U

    Electrostatic potential energy in a circuit with and without a battery

    I have two plate capacitors serially connected in a circuit with a battey and a switch between the battery and one of the plate capacitors. I have two situaions: a) I charge the capacitors, cut the switch, and double the internal distance in one of the capacitors. b) I charge the...
  22. J

    What is electrostatic potential

    I can't understand what actually is the electrostatic potential.The definition given in my textbook is as follows : "Electrostatic potential at any point in a region of electrostatic field is the minimum work done in carrying a unit positive charge from infinity to that point without...
  23. facenian

    Electrostatic uniqueness theorem

    There is one thing I don't understand about this and is that besides the Dirichlet and Neumann conditions there seems to be a third one which is important when the method of images is used and is never mentioned. The problem is that Newmann condition requires especification of \frac{\partial\phi...
  24. F

    Iron core for Electrostatic coil

    I am just an electrician doing experimental work with a Stubblefield coil. From what I've read the most common steel is 1018. If Stubblefield used a common bolt I assume this would fall into the 1018 realm. Would the 1018 iron core be better cold rolled or hot rolled for the magnetic collapse as...
  25. B

    Electrostatic Force diagram

    Two positive point charges, each of which has a charge of 1.5 × 10−9 C, are located at y = +0.50 m and y = −0.50 m. The Coulomb constant is 8.98755 × 10^9 N · m2/C2. a) Find the magnitude of the resultant elec- trical force on a charge of 1.0×10−9 C located at x = 0.55 m. Answer in units...
  26. F

    Why is the electric energy density in classical electromagnetism underspecified?

    http://farside.ph.utexas.edu/teaching/em/lectures/node56.html By equation 595, electric energy in the universe caused by an electric field is derived as http://farside.ph.utexas.edu/teaching/em/lectures/img1261.png. However, how come you can differentiate with respect to volume and say that...
  27. Z

    Electrostatic Potential Question - Basic physics

    Hi Everyone! I'm new to this forum, and English isn't my first language - I would really appreciate your help with this question :) Homework Statement http://img225.imageshack.us/img225/3807/1milliontotheground.jpg there are given 2 thin shells with radiuses b and c, and a full sphere...
  28. M

    Is the Electrostatic Motor Affected by Changes in Earth's Ionization?

    Hello I wanted some feedback on the idea I have about this electrostatic motor. One thing not mentioned is that the electrostatic field of the Earth is changing from day to night because of the ionization from solar rays is stronger during the day. Yet I wonder if the motor would stilll run for...
  29. S

    How Does Changing Voltage Affect Particle Descent Time?

    Homework Statement Two parallel plates are positioned horizontally and when the potential te?difference between the plates is 400 V, a charged particle is suspended freely 10 cm above the lower plate. If the potential difference is suddenly changed to 200 V, how long will it take the particle...
  30. V

    Electrostatic potential of a split sphere, using the laplacian for spherical coord

    Homework Statement Two concentric spherical shells. The outer shell is split into two hemispheres at potentials +Vo for the upper half and -Vo for the lower half. The inner shell is at zero potential (see attachment). " what is the potential in the region; r > R' " (the potential in the...
  31. T

    Conducting Spheres in Electrostatic Equilibrium

    Homework Statement Homework Equations potential, V = kq/r where k is 1/4 pi epsilon conservation of charge, sum of q = Q The Attempt at a Solution what i did is let q1 + q2 + q3 = 4*10^-4 then let V1 = V2 = V3 and solve for q3 but i end up getting q3 = 0.0002 which is...
  32. M

    The 3rd law of Newton with electrostatic fields

    Well, say there is an positive particle, and a negative particle. Newton said one is pulling the other, and thus it is pulling back. But we now know both particle actually creating fields, and the fields actually exerting the force on the other particle. so basically, this is not action...
  33. R

    Electrostatic and gravitational forces

    Homework Statement How far (in cm) apart must be proton from group of 13 protons if the magnitude of the electrostatic force acting on either one due to the others is equal to the magnitude of the gravitational force on a proton at Earth's surface? So, I know that the mass of a proton is...
  34. T

    How do I tell if the field is a possible electrostatic field?

    If I have a picture of the field lines of a field, how do I tell if the field is a possible electrostatic field? What are some things to look for that would imply it either is or is not a possible electric field?
  35. Ranku

    Meaning of formula of electrostatic force

    The formula for Coulomb's force is F = k \frac{q_{1}q_{2}}{r^{2}}, which represents how the force varies as the inverse square of distance between like or unlike charges. Does it mean the repulsive force between like charges decreases as the inverse square of distance?
  36. T

    Electrostatic Effects and Energy Level Splitting

    Textbook: "Chemistry" by Silberberg. 5th Edition. Page 306 "Electrostatic effects play a major role in determining the energy states of many-electron atoms." Can someone help me understand this statement? "Electrostatic effects" is not in the textbook glossary, and I'm not having luck...
  37. G

    Electrostatic Potential Energy of a Conducting Sphere

    Homework Statement Determine the total electrostatic potential energy of a conducting sphere of radius r_0 that carries a total charge Q distributed uniformly on its surface. Give your answer in terms of Q, r_0, epsilon_0 and appropriate constants. Homework Equations The Attempt at...
  38. K

    What is the potential of the bigger sphere when the smaller sphere touches it?

    Homework Statement A spherical conductor of radius 2 m is charged to 120V. It is now placed inside another hollow spherical conductor of radius 6m. Calculate the potential to which the bigger sphere would be raised if the smaller sphere were made to touch the bigger sphere. Homework...
  39. K

    What is the work done by the electrostatic force

    Homework Statement A spherical shell of radius 'a' and charge Q is expanded to radius 'b'. What is the work done by the electrostatic force in this process? Homework Equations Method 1 Work done = initial energy - final energy Method 2 Work done = Q (potential difference between...
  40. C

    Calculating Mass to Balance Electrostatic Field on See-Saw

    b]1. Homework Statement [/b] A see-saw with a central pivot is made of insulating material. the left hand side supports a conducting sphere of charge Q= 5.0x 10-6 which experiances an electrostatic force from an idetical sphere 10cm below with +Q the right end has anouther conducting sphere of...
  41. L

    Electrostatic Potential homework

    Homework Statement A test charge +q is brought to a point A a distance r from the center of a sphere having a net charge +Q. Next, a test charge +2q is brought to a point B a distance 2r from the center of the sphere. Compared with the electrostatic potential at A, the electrostatic potential...
  42. S

    Electrostatic Potential of 4 charged spheres on corners of a square

    Homework Statement Four idential charged spheres are located at the corners of a square with side length 2a. The spheres are much smaller than the size of the square (r<<a) and each sphere has a mass m and carries the same charge -Q. a) What is the total electrostatic potential energy of...
  43. S

    Electrostatic Potential for Two Concentric Cylindrical Shells

    Homework Statement Two very long hollow conducting cylindrical shells are situated along the x-axis. The shells are concentric and have negligible thickness. The inner shell has a radius a and a linear charge density +lambda, while the outer shell has a radius b and a linear charge density...
  44. E

    Laplacian of electrostatic potensial

    Something occurred to me just now. A question about the scalar potential. First I will do some calculations of the laplacian of the scalar potential in different electrostatic situations to give myself a basis for my question. Point charge: \phi =\frac{1}{4\pi\epsilon_0} \frac{q}{r}...
  45. S

    Particular material that becomes strained under electrostatic

    I am currently looking for a particular material that becomes strained under electrostatic or magnetic fields. I am new to the world of solid state physics and I was interested on doing a research project on the studies of the electrostriction effect. Thank You
  46. A

    Electrostatic potential independent of distance?

    Say I have a packet of electrons just sitting there, before they repel each other, what is their potential energy? I have no idea of how to calculate their potential energy since at r = 0 , U = infinity, which is not helpful since my problem requires U to be finite but the only way I know of...
  47. S

    Electrostatic force problems, help

    Electrostatic force problems, help urgent! Homework Statement Question: An isolated hollow metal sphere of radius 40 cm carries a charge of -10*10^-6. What is the magnitude of the electric field E (a) in the empty space inside the sphere and (b) 60 cm from the center of the sphere ( no...
  48. M

    Electrostatic problem (point charges)

    Homework Statement http://www.freeimagehosting.net/uploads/3e00ce8695.gif Homework Equations Electric field equation derived from Coloumb's Law (given on the screenshot above). The Attempt at a Solution Solution is given in the form of answer sheet...
  49. V

    Minimum distance & electrostatic potential energy

    An alpha particle (made of 2 protons and 2 neutrons) with initial kinetic energy of 1.20 × 10^-12 J travels directly towards the nucleus of the stationary zinc atom The nucleus of a zinc atom contains 30 protons and 35 neutrons, and has a diameter of 4.00 × 10^-13 cm. The alpha particle slows...
  50. S

    D What is the Missing Step in this Electrostatic Algebra Equation?

    Homework Statement I have a homework question on electrostatic seesaws. My problem is the algebra. Homework Equations I have been following another example and any guidance to help me proceed would be great. 0= (2q Q)/(4πε_o r²)+(q Q)/(4πε_o r²)-m 0= (3q Q)/(4πε_o r²)-m m=(3q...
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