What is Electrostatic charges: Definition and 38 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

    I Preventing Corona Discharge from Wimshurst Machine

    Hey all, new here. Just finished my first wimshurst machine and I’d consider it to be fairly AWESOME! Having a blast so far. The thing is, I believe that given the parameters of my build (# of sectors 24, diameter 11”, etc) I’m not quite getting max voltage possible and I’ve confirmed this at...
  2. J

    Method of mirroring - metal plates

    Hi, I'm having some trouble understanding how to solve this problem. I have a few questions: 1. I understand that I need to make an educated guess for the electric potential, where \(V_1\) is given by: V_1 = \frac{q}{4\pi\epsilon_0} \left(\frac{1}{r_1} - \frac{1}{r_2} + \frac{1}{r_3} -...
  3. Lotto

    Why is a small nut attracted to a straw whereas it should be repulsed?

    TL;DR Summary: I have a small nut tied to a string. I take a straw and generate free electrons on it by a handkerchief. Then I thouch the nut with the straw and the nut is to be repulsed by it, because of a transfer of part of its electrons. But it does not happen, the nut is attracted to a...
  4. bryanso

    B Static Point Charge Should Have Zero Effect

    How can we detect electrical effect of a static point charge at all? I think of a point charge like a sea urchin. With field lines going outwards in all directions (for +ve). So the vector pointing at me directly should be canceled perfectly by the vector going away from me. And so each line...
  5. C

    I Where to find this uniqueness theorem of electrostatics?

    There is a nice uniqueness theorem of electrostatics, which I have found only after googling hours, and deep inside some academic site, in the lecture notes of Dr Vadim Kaplunovsky: Notice that the important thing here is that only the NET charges on the conductors are specified, not their...
  6. emmanual

    Electric field due to three point charges

    I've calculated the intensity for every point charge which are EA = 6.741 x 10¹³ NC¯¹ EB = 4.494 x 10¹¹ NC¯¹ EC = 6.741 x 10¹³ NC¯¹ and I am pretty sure about this far but I am struggling to calculate the X-axis intensity and Y-axis intensity to find the entire approximate intensity with the...
  7. A

    B Problems I Have With Electrostatics and Pith Ball Experiments

    As a preliminary note, most people flex about how dumb questions and then continue to school and scold curious minds. Instead of taking a demeaning approach I just ask for respectful insight to quench curiosity. I will 1) explain the experiment as I know it to be, 2) explain what I have been...
  8. nazmulhasanshipon

    Comparing energy lost by the battery & energy gained by the capacitor.

    Imagine the two terminal of a *parallel-plate capacitor* are connected to the two terminal of a battery with electric potential difference #V#. If the capacitance of the capacitor is #C#, and the area of each plate is $A$. In this process would the energy lost by the battery and the stored...
  9. A

    B Electrostatic charge build up in environmental electron microscopy

    Hello, If I understand it correctly, the samples are grounded inside a scanning electron microscope (SEM) to avoid charge build up through the electron beam. Also the non-conductive are coated with a conductive layer, so they can be grounded as well. However, I do not know how the charge build...
  10. Anjum S Khan

    Can positive charge move between charged bodies like electrons do?

    Suppose , there is a body B1(-vely charged) and body B2(+vely charged). When both are on contact, electrons move from B1 to B2 as B2 is having electron deficit. But is reverse also possible that protons move from B2 to B1 as B1 is having proton deficit.
  11. Hawkingo

    Why the work done is negative when bringing 2 opposite charges together?

    we know that if the applied force is in the direction of the displacement then work done is positive.But in case of bringing 2 opposite charges from infinite to a certain distance,the work done is negative even the force and the displacement of the charge is in the same direction. From...
  12. P

    Calculate the magnitude and direction of the torque

    Homework Statement [/B] a) (a) Assuming the HCl molecule consists of point-like ions (H+ and Cl) separated by 1.0 * 10^-10m, find the dipole moment of the molecule. b) Calculate the magnitude and direction of the torque exerted on this dipole if the molecule is subjected to an external electric...
  13. CDL

    Point Charges on a Polygon with another Charge in the Middle

    Homework Statement Suppose we have a regular n-gon with identical charges at each vertex. What force would a charge ##Q## at the centre feel? What would the force on the charge ##Q## be if one of the charges at the vertices were removed? [/B]Homework Equations Principle of Superposition, the...
  14. H

    Finding the Total Charge of a Non-Uniformly Charged Disc

    Homework Statement I have a disc with radius R. One half has the charge density of +2σ and the other half has −σ. The task is to find the total charge of the disc. Homework Equations dQ=ρ2πr^2 I would use this equation if the charge density was uniform The Attempt at a Solution My first idea...
  15. ubergewehr273

    Problem in electrostatics: E-field near 2 point charges

    Homework Statement Refer the image. Homework Equations kq1q2/r^2 = F Potential energy = kq1q1/r The Attempt at a Solution Obviously since both charges are unequal in magnitude option a is incorrect. Calculating field at large distance r, E = kq1/r^2 - kq2/r^2 = kq2/r^2 Also potential energy...
  16. H

    Electrostatic energy after a metal piece is inserted between 2 capacitor plates

    Homework Statement fig 1 : Area of each plate is S, separated by 2d, charge Q in the capacitors fig 2 : uncharged conductors of area S, thickness d, inserted parallel between plates What is the ratio of electrostatic energy in fig 2 to electrostatic energy in fig 1? Homework Equations Q =...
  17. JustAStudent

    Calculate the total force on Q1

    Homework Statement Q1<------>Q2<------>Q3 In the above figure, the distance between Q1 and Q2 is equal to the distance between Q2 and Q3. That distance is R=1.5 m. Q1= 2.24x10-6 C, Q2=+Q1 and Q3=-Q1. Calculate the total force on Q1. Give your answer with a positive number for a force...
  18. Sajid Nabi

    Electrostatics: Finding force experienced by charge

    1. Find the magnitude and direction of the force experienced by the charge of 3microcoulombs.Homework Equations After subtending forces of both the particles on the third one, we need to find the aggregate magnitude of the charge experienced by it. The Attempt at a Solution I was able to find...
  19. Mason Smith

    How do I find the points where the electric field is zero?

    Homework Statement Two pairs of charges are shown in Figure 1. Homework EquationsThe Attempt at a Solution I originally thought that the electric field past point 7 (i.e. points 8,9, 10) was the solution. However, this is wrong. I then considered point 1, yet that was wrong too. I even...
  20. harini07

    Electrostatics: Charging a sphere by induction

    Homework Statement this is a theoretical question.please consider the situation as follows: we are charging a metallic sphere using induction phenomenon with the help of a postively charged metallic rod and while on grounding the electrons flow from the ground to the sphere rather than sphere...
  21. D

    Consider the configuration consisting a +q charge....

    and two -q charges aligned along the x-axis as follows... -q__________q__________-q <--- the space between them being d a) Suppose the +q charge is displaced perpendicularly by a small vertical distance dy. What is the total force F acting on it? Taylor expand your answer to leading order in...
  22. UseAsDirected

    B Why are two cellophane tapes attracted when ripped apart?

    Hello, I put two strips of cellophane tape adjacent to each other adhered onto a table. When I pull them both apart, they repel each other, both insulators ripped electrons from the wood. When I stack two strips of tape on top of each other on a table, rip the combined bundle off the table...
  23. V

    Charged Capacitor: Opposing Emf Battery Series

    can a charged capacitor mathematically be represented as uncharged capacitor connected in series with battery of opposing emf ?
  24. B

    Solve Gauss' Law Question: Find Max Acceleration of Two Balls

    Homework Statement Consider two balls of equal radii and masses but opposite charges, distributed uniformly over their volumes. Initially, the balls are at rest and far away from one another. Due to the Coulomb attraction, the balls start moving towards each other. The balls can be treated as...
  25. Monkey_Man08

    What is the unknown charge if the net electrostatic force on particle 1 is zero?

    1. The problem statement: In the figure four particles form a square with edge length a = 2.44 × 10-2 m. The charges are q1 = q4 = 1.06 × 10-15 C and q2 = q3 = q. What is q if the net electrostatic force on particle 1 is zero? All variables and given/known data: The given variable are in the...
  26. Y

    What Is the Potential at the Center of Concentric Metallic Spheres?

    Homework Statement A metallic sphere is placed inside a hollow spherical shell. The potential on the inner and outer spheres is 10 V and 5 V respectively. What is the potential at the center?(The spheres are concentric.) Homework Equations $$V =\frac{kq}{r}$$ The Attempt at a Solution The...
  27. B

    Problem with Net Coulombic Force

    Homework Statement Consider an ## n ##-dimensional solid sphere of radius ##R##, with uniform charge-density and a total charge ##Q##. A charged particle ##q## is kept at a distance of ##r## from the center. For ##r<R##, what is the Net Coulombic Force experienced by the particle? If it is in...
  28. J

    Electrostatic Force Between Proton and Neutron?

    After calculating the force upon an electron and a force upon a proton in the atom of hydrogen, my result was a force of ≈8.2x10-8 Newtons acting upon the electron and proton each. If found this by using the formula Fe = (ke q1q2)/r2 Taking this number, I then applied it in the formula F = ma...
  29. S

    + charged sphere and - charged sphere touch and separate

    Homework Statement A small metal sphere X is charged by losing 500 electrons. An identical metal sphere Y is charged by gaining 1000 electrons. The two spheres are first put in contact with each other and then separated. If -e is the charge on an electron, what is the charge on each sphere...
  30. Neil Graham

    Differences in Repelling Charges

    Simply, is there a difference between a positive charge repelling a positive charge and a negative charge repelling a negative charge. More of what I am asking, is there any special properties that one has over the other, and vice versa.
  31. D

    Understanding Electrostatic Charges: A Short Quiz

    Homework Statement Select the answers which complete the statements below (e.g., if answer A completes the first statement, and answer B the others, enter ABBBB).A) positive B) negative C) neutral D) cannot tell A positive point charge is brought near the outside surface of a neutral...
  32. 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...
  33. Roodles01

    Forces on symmetrical electrostatic charges

    Homework Statement 3 point charges L(-b, b) M(b, b) & N(0, 0) have charges Q, -3Q & Q. I need to find the force on the charge at the origin. Homework Equations Coulomb's Law important, here. F = 1/4∏0 q^2/r^2 r(hat) z-component no existent (from coordinates given) x- & y-components to...
  34. C

    Electrostatic charges on a cotton yarn

    Usually, in textile industry, the important issue is to discharge the yarns from any electrostatic charges that might be stuck on it due to friction or other factors. What I need is completely the opposite; I want to put, on a yarn, electrostatic charges strong enough to make the yarn stuck on a...
  35. K

    Electrostatic Equilibrium on the x-axis

    Question - Three charges lie along the x acis as shown below. The negative charge q1 = 25 uC is at x = 2.0 m, the negative charge q2 = 6.0 uC is at the origin. Where must a positive charge q3 be placed on the x-axis such that the resultant force on it is zero? Answer - I was thinking the...
  36. C

    Verifying Electrostatic Charges: Q and q

    I have attempted this problem twice and have one more chance before I get the "red ex" so I thought I'd check my thinking. Two identical conducting spheres, fixed in place, attract each other with an electrostatic force of 0.136 N when their center-to-center separation is 65.0 cm. The...