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. N

    Dielectric in an electrostatic field

    Hi all, I am sorry this could sound like heard many times before, but I am trying to understand this problem and found nothing in my physics books. If I put a small dielectric (bit of paper) into an electrostatic field (for example generated by a rubbed plastic rod), the paper will be...
  2. E

    Help Needed: Modeling Beam Bending with Electrostatic Forces

    Hey-- I'm trying to model the bending of a beam due to electrostatic forces. (Femlab does offer this model on their website, but the module I'd need to run it costs $600!) I have no problem modeling a beam bending, and I have no problem creating a parallel plate capacitor, but when I...
  3. B

    Question on electrostatic pressure

    I am currently working through section 2.5 of Griffiths' electrodynamics, specifically the part which deals with electrostatic pressure in conductors. I encountered the following question (question 2.39, or 2.38 in earlier versions): A metal sphere of radius R carries a total charge Q...
  4. J

    Maximum electrostatic force problem

    im studyng electromechanics and this is a problem i found gived a fixed point A charged with Q1 charge, gived a electrical wire of fix length L and charge Q2 distributed uniformly in it, the wire is fixed at its edges at 2 points along a line L, the line L and the point A are separated by...
  5. S

    Calculating Electrostatic Force of 3 Point Charges

    Three identical point charges of 2 micro C are placed on the x-axis. The first charge is at the origin, the second to the right at x = 50 cm (.5 m), and the third at the 100 cm (1 m) mark. What are the mag. and direction of the electrostatic force which acts on the charge on the origin? The...
  6. maverick280857

    What is the Electrostatic Potential at Any Point on a Spherical Shell Due to an External Point Charge?

    Potential at ANY point on a spherical shell due to external point charge Hi everyone Here is another problem: A point charge q is placed at a distance of r from the center of an uncharged conducting sphere of radius R (< r). Find the potential at any point on the sphere. I know the...
  7. C

    Understanding Electrostatic Potential Energy Calculations

    http://forum.lowyat.net/index.php?act=Attach&type=post&id=46273 Hi there, I've been trying this question quite long but I do not get the answer, could anyone help me? For part one, i got the answer... part (ii) ... i saw it in a book saying i suppose to choose a point to get the...
  8. L

    How Does Electrostatic Force Affect Neutral and Charged Spheres?

    Sphere A carries a net charge and sphere B is neutral. Both are conducting spheres and they are placed near each other on an insulated table. Which statement best describes the electrostatic force between them? a) there is no force b/w them since one is neutral b) there is a force of...
  9. M

    What Happens to the Charge When Two Insulated Spheres Touch?

    I have just started electricity in physics and am wondering how to do this homework questions. The question is: Sphere A and B are insulated metal spheres with charges of +10 micro C and -5 micro C respectively. If sphere A has twice the radius of sphere B, what will be the charge on each...
  10. A

    Electrostatic Force Derivitive

    Well,I've tried attempting this problem but I am not sure if I approached it the right way. Here is a link for the diagram and the question. [PLAIN]http://img.photobucket.com/albums/v367/crazy_cat_lady/physics/diagram1.bmp[/URL] If anyone could check it over and point out any mistakes...
  11. M

    How Does Electrostatic Force Affect Charges Within a Uniformly Charged Sphere?

    Consider a solid sphere of radius R containing a total charge Q which is uniformly distributed throughout the volume with a volume charge density rho. a) find the total force exerted by the electrostatic field on the charge in the 'northern hemisphere'. express your answer in terms of the...
  12. F

    Electrostatic force, Newtons and Distance

    Have a problem that I'm not sure how to approach any help would be appreciated! If the electrostatic force between two protons is equal to 1x10^-7 Newtons, what is the distance between them?
  13. D

    Electrostatic Speakers: Understanding Theory and Model

    Trying to understand some course material and I decided to look into electrostatic speakers. I can't seem to apply electrostatic theory formulaes to the speaker model. There are two stators and a diaphragm in the speaker, my current guess is that the two stators act like a capacitor and hence...
  14. H

    Mean Value Theorem and electrostatic potential

    Prove that for charge-free two-dimensional space the value of the electrostatic potential at any point is equal to the average of the potential over the surface of any circle centered on that point. Do this by considering the electrostatic potential as the real part of an analytic function...
  15. I

    Electric fields and electrostatic forces

    Electric fields and electrostatic forces (1 question) I was wondering if someone can show me how to answer this problem. Thank you. 1)Two charges are placed on the x-axis, an unknown positive charge at x=0 cm and a negative 8.642e-6 C charge at 2.993 cm from the origin. Calculate the...
  16. A

    Confused: Determining Net Electrostatic Force and Direction

    Could someone please help me figure out how to determine the net electrostatic force and direction in this question? I have completed what I believe to be the first portion using Coulomb's Law for the force acting on the origin charge (F12 and F13) A charge of -3.0 micro C is fixed at the...
  17. P

    How Do You Calculate Electrostatic and Gravitational Forces in a Helium Ion?

    Can someone help me with this problem: Consider a simplified model of the singly-ionized helium atom, He+: 2 protons plus 2 neutrons in the nucleus, "orbited" by one electron at a constant distance of 2.65 x 10^-11m. a. What is the magnitude of the attractive electrostatic force between...
  18. J

    What is the force between two point charges at a 45 degree angle?

    Point charges q1 and q2 are placed in space, with q1 at the origin and q2 a distance r from q1 making a 45 degree angle with the horizontal. a) Find the force using unit vectors i and j from q1 to q2 b) " " from q2 to q1 c) If q1=q2, what is...
  19. S

    Electrostatic and gravitational potential energy question

    Hi all, I have a few questions that I'd appreciate some guidance on. There are two identical dust particles:- mass 13ug charge +9.8E-15 C electrostatic potential energy 8.7E-17 J gravitational potential energy 1.1E-24 J The mass is given in the question, the energies I calculated...
  20. S

    Net Charge of -59uC: #Electrons & Mass Increase

    A person accumulates a net charge of -59uC, how many excess electrons does this person get and by how much does her mass increase?
  21. G

    Electrostatic Field Energy of Electron

    Doing my physics homework a few weeks ago led me to some startling conclusions (this doesn't really happen often, don't worry too much.) We were learning about electrostatic field energy, and I was doing a problem involving the finding of the electrostatic field energy of a sphere, but later in...
  22. Rockdog

    Electrostatic force problem help with vector parts

    I've included a picture. Two charges Qc and -Qc(Qc = 4 µC) are fixed on the x-axis at x = -7 cm and x = 7 cm, respectively. A third charge Qb = 5 µC is fixed at the origin. A particle with charge q = 0.3 µC and mass m = 5 g is placed on the y-axis at y = 14 cm and released. There is no...
  23. Rockdog

    Electrostatic force problem help with vector parts

    I've included a picture. Two charges Qc and -Qc(Qc = 4 µC) are fixed on the x-axis at x = -7 cm and x = 7 cm, respectively. A third charge Qb = 5 µC is fixed at the origin. A particle with charge q = 0.3 µC and mass m = 5 g is placed on the y-axis at y = 14 cm and released. There is no...
  24. B

    The electrostatic potential

    1}If the electric field is zero in some region, must the potential also be zero?An example? 2}Give an example of a conductor that is not an equipotential.Is this conductor in electrostatic equilibrium? 3)If a high voltage cable falls on top of your automobile, will you probably be safest...
  25. M

    What Charge Must an Oil Droplet Have to Balance Gravity in an Electric Field?

    Don't know where to go Get stuck at every corner. Here it is "A small droplet of oil of 50^10*-6m radius is sitting inside of an electric field 500^10*3 N/C which is pointing straight up. What must be the charge on the oil droplet so that the electrostatic force cancels out due to gravity? The...
  26. G

    Strong Nuclear Force and Electrostatic Force

    there are two forces, the nuclear force which binds protons and neutrons together. However as the size of the nucleus gets larger the electrostatic force of repulsion in the nucleus overcomes the strong nuclear force. so larger atoms breakdown to form smaller atoms, why does the electrostatic...
  27. I

    Electrostatic Force Question: Am I Right?

    Here is the question... A pith ball of mass 1.5g is suspended along a string which is attached to a non movable point, when a pith ball of equal charge and mass is brought close to the original pith ball. A state of equilibrium is reached and the pith balls are 2.6cm apart and the string...
  28. C

    Compression of an electrostatic charged sphere

    "compression" of an electrostatic charged sphere Everytime i propose a new motion machine from my ignorance or misunderstunding of physics, your explanations solve some questions, but open new others: I proposed a system that acumulated electrons on a sphere surrounded by an electrons...
  29. C

    Electrostatic Paradox: Exploring the Surprising Behavior of Connected Conductors

    Hello everybody! Many changes since the last time i was here!. Now, I've got a question that i can't stop think about. I hope you could help me. We all know the excess of charges on connected conductors always tends to distribute equally... ALWAYS? Take a look to this animation...
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