Electrostatic Definition and 884 Threads

The exciton is defined as a bound state of an electron and an electron hole. From what I've read, this state is described by Coulomb's law. Coulomb's law describes the interaction between two charged particles. So my question is: because an electron hole is not an actual particle, how does an...

I currently live in Mongolia, and during the winter months (6 months of the year) we heat our "Gers" see below picture, using coal. These are burned in stoves, and then the smoke is funnelled through a 11cm tube (chimney) through the roof. However this is very smoky and nasty, and bad for...

Homework Statement Two point charges, +4 μC and -10 μC are placed 10 cm apart in air. A dielectric slab of large area and thickness 5 cm is placed between the charges. Find the force of attraction between the charges, if the dielectric has a dielectric constant of 9. Homework Equations...

Homework Statement A unit sphere at the origin contains no free charge or conductors in its interior or on its boundary. It is, however, embedded in a dielectric medium. The dielectric is linear, but the permitivity varies by angle about the origin. It is constant along any radial direction...

I'm a little stumped with this problem, I have posted a photograph below as there is a diagram to compliment the questionExpressions which I used where V(r)= k q/r Where q= σ da Where da is an element of area And k= 1/4πεI messed around with these expressions for a while but it didn't really...

I have a question about electrostatic fields! I was given these two equationsE= k [xy xˆ + 2yz yˆ + 3xz zˆ] E= k[y^2 xˆ+ (2xy+ z^2)+ 2yzzˆ] And asked to determine if either could be an electrostatic field, I'm not asking how to solve this problem but I'm not sure what defines an...

Shielding -- Need to ground an electrostatic shield? I am reading this app note by analog devices: http://www.analog.com/static/imported-files/application_notes/41727248AN_347.pdf At the bottom of the first page it says: "An electrostatic shield, to be effective..." "But grounding the...

I was wondering whether you could trap a cation simply by putting it inside a positively charged sphere. Is this possible?

While investigating Coulomb's Law, I created a graph of F-1/2 vs. r to display results. The gradient of this graph is much steeper than it should be. What factors could affect the electrostatic force to make this happen? Any suggestions would be greatly appreciated! (The experiment...

How does electrostatic force vary between two objects if the distance is doubled? I know with gravitational force as the distance doubles the force decreases by \(\frac{1}{4}\).

I need to perform a demonstration of electric forces. Something more substantial than weak static charge forces would be best. Could someone please help me by describing a practical way for me to put a charge onto something lightweight and then generate an electric field to move it back and...

A long straight metal rod has a radius of 5 cm and a charge per unit length of 30 nC/m. Find the electric field x cm away where distance is perpendicular to the rod.The solution to this uses ## \int E\cdot dA = \dfrac{q_{encl}}{\epsilon_0}##. My question is, why can you use this? I thought...

Does anyone here know a source, where the equation of motion for a massless charged particle (which of course does not exist in Nature as far as we know) in a homogeneous electric field is actually solved? I googled, and there are some papers about this, but the equations are never actually...

Homework Statement Two 0.115-gram pith balls are suspended from the same point by threads 22.0 centimeters long. When the balls are given equal charges, the two strings form an angle between them, and the balls come to rest 15.0 centimeters apart. Neglect the mass of the thread. What is the...

Hi Guys--and Gals? Here's a wierdie; One is always collecting potential on our bodies, frequently called electrostatic voltage. I've found sound research that it is beneficial to "earth" or ground ourselves as often as possible to drain this off. Those last words are the question: does this...

Homework Statement Say there is a charge of +3 at the origin and a charge of -7 at .5m Where would a third charge of arbitrary sign have to be for equilibrium to be reached?Homework Equations The Attempt at a Solution so I've widdled this down to 3 / r^2 = -7/(.5+r)^2 but am having problems...

I understand that voltage depends on how far the electrons are, so for a sphere it would be q*k / r. But what if a sphere with 100kv , then we put with contact to it a metal box , becoming on body, will the volt remain 100kv

Hello everyone I am stuck with a problem about voltages (electrostatic potential) and forces. According to capacitor equations the energy stored in the capacitor is: U=1/2*C*V^2 And force is: F = - dU/dx Since U is dependent on V^2, our force can’t be positive (repelling...

I have read that in electrostatic equilibrium, their are no electric fields or else the charges would be moving. So given a positively charged spherical shell, the positive charges would repel each other and reside on the outside, causing the shell to be in electrostatic equilibrium. But if...

Find the electrostatic self potential energy of a spherical charge distribution with charge density \rho and radius R. The self potential energy is the work required to increase the radius of the sphere from r to r+dr.

Hello every one. Hope you are doing amazing. I am new to the forum and I hope I am putting the post under appropriate thread. Please feel free to guide me through rules if I do mistakes. I will honor every ones reply over my little project. I am making a small glove box which is inclined...

In Griffith's section about electrostatic boundary conditions, he says that given a surface with charge density \sigma , and take a wafer-thin Gaussian pillbox extending over the top and bottom of the surface, Gauss's law states that: \oint_{S} \mathbf{E} \cdot d \mathbf{a} =...

I have a question pertaining to mathematically possible E fields. I've always known the curl of the field has to be zero for the field to be a possible electric field, but is this the sole determining factor? What about if the potential is some wonky function that doesn't seem plausible, and...

So I'm getting confused by my textbook, and having problems finding any straight forward answers online. I am studying Gr.12 physics myself, so I don't have a teacher. I understand the nature of charges, but somehow I'm getting mixed up when dealing with non-conductive materials. Basically, I...

Homework Statement A single isolated proton is fixed on a surface. Where must another proton be located in relation to the first in order that the electrostatic force of repulsion would just support its weight? 2)Two identical objects have charges from +6.0*10^-6 and -2.0*10^-6...

Hey everyone, so I think my question will be relatively simple compared to what I've viewed elsewhere here. Basically, I am an adult taking grade 12 physics as self study, and for the most part I can work things out ok. I am planning on taking the diploma exam for my province in January...

Homework Statement A metal sphere of radius R carries a total charge Q, what is the force of repulsion between the northern and southern hemispheres Homework Equations \large f=\sigma Eav=1/2 \sigma(Eabove+Ebelow). \\Fz=\int fz dA =\int \sigma Eav cos\theta R^{2}sin\theta d\theta d\phi=\int...

Hi Q 1 An electrified rod attracts pieces of paper. After a while these papers fly away. Why? My Answer: Due to the phenomenon of electrostatic induction, the paper becomes charged and will be attracted towards the rod. After some time, the charge becomes neutral and paper flies. Q...

What is the criteria in choosing infinity as zero potential ? e.g. an infinite plate with uniform charge density. What is the physical meaning of not be able to choose a position as reference potential ??

Homework Statement Find an expression for the electrostatic self-energy of an arbitrary spherically symmetric charge density distribution ρ(r). You may not assume that ρ(r) represents any point charge, or that it is constant, or that it is piecewise constant, or that it does or does not cut off...

A scalar potential ##\phi: \mathbb{R}^4\to\mathbb{R}## has the physical unit of energy per particle property, which can be charge or mass. Take the positional derivative and multiply by the particle property to get the force on the particle. So far gravitational and electric potential are the...

Problem #1 A slab of thickness 2a (extending infinitely in the y and z directions) with non-uniform charge density is parallel to the yz-plane. The charge density is given by ρ(x) = γx2, -a < x < a where γ is a constant. 0, a < |x|. (a) Use Gauss's law plus symmetry to find...

Homework Statement Consider a series of three charges arranged in a line along the z-axis, charges +Q at z = D and charge -2Q at z = 0. (a) Find the electrostatic potential at a point P in the x, y-plane at a distance r from the center of the quadrupole. (b) Assume r >> D. Find the...

Hi all, Work done to move a charge between two points in electrostatic field is independent of path taken. what is in this electrostatic force that is causing this? I mean how is it making it path independent? Does it has to do with the inverse-square nature of the field? or Its radially...

Homework Statement Why does this expression, given in cylindrical coordinates, rapresent an electrostatic field: $${\bf E(r)}=\frac{\alpha}{z^2}{\bf u_r}-2 \frac{\alpha r}{z^3}{\bf u_z} $$ Homework Equations The Attempt at a Solution I can't understand why the expression rapresent...

Homework Statement The figure shows a uniformly charged thin rod of length L that has total charge Q. Find an expression for the magnitude of the electrostatic force acting on an electron positioned on the axis of the rod at a distance d from the midpoint of the rod...

1. The problem is in the attachments. 2. Field strength is equal to voltage divided by distance 3. I want to make sure that i understand a few things before i solve this problem! i would like to know your opinion! a) first, field strength is inversely proportional to the the distance squared...

Homework Statement A space probe travels towards a planet measuring the electrostaticpotential as it approches. the electric field strength is -500 N/C at the altitude of 600,000 KM and it decreases steadily until it reaches -400 N/C at 580,000 KM above the planet's surface . find the...

what is the work done by electric forces in moving a charge Q=1 nC from the origin to the point (1m, 1m, 1m) in the electrostatic field given by E=(x,y,z) = (x* (a sub x) + y^2*(a sub y) - (a sub z) V/m in the Cartesian coordinate system along the straight line joining two points?

How do I know if E (electric field) and \Phi (electrostatic potential) is continuous at the surface? I'm asking this because I have a problem choosing which formula to use, if you know what I mean. There are a lot of formulas for E and \Phi .

Is electric potential always continuous in an electrostatic field? I mean, does it suffer from discontinuity at any point?

electrostatic induction... when a conductor is charged by the method of induction,is its charge equal in magnitude to that of inducing charge or somewhat less?

Homework Statement A small, positively charged sphere is released from rest and moves directly away from a larger, positively charged sphere. During this process, the electrostatic force: a) does positive work and increases the kinetic energy of the small sphere b) does negative work and...

Homework Statement There are 2 small metal balls of radius r1 and r2 and are kept at very large distance , what should be ratio of charges on them for electrostatic energy to be minimum Homework Equations E=Q^2/(8πϵR) Self Energy The Attempt at a Solution In this problem, electric...

Homework Statement A conducting sphere of radius ##a## carries an initial charge ##q_o##. It is surrounded by another concentric sphere of radius ##b##. The space between the two spheres is filled with a dielectric of permittivity ##\epsilon## and conductivity ##\sigma##. Find the electrostatic...

Homework Statement I'm currently tackling parts (a) and (b) of section ii) decribed here:http://puu.sh/31KIZ.png Homework Equations V=(q/4∏ε)*(1/r) The Attempt at a Solution From the first section (i) calculating the potential was relatively straight forward since we were only...

Homework Statement Homework Equations The Attempt at a Solution I've done part (a) and (b) using conservation of momentum and energy..for part (c) I'm not sure how to find the minimum angle ∅. I have also worked out the velocities of m1 and m2 just before the collision as...

einstein explained the origin of gravitational force from the concept of space time curvature.but what about the electrostatic force...does it also originate from some sort of curvature.please explain...

Homework Statement Using Stoke’s theorem and the identities given, ∇x∇(Scalar)=0 deduce the relationship between electrostatic field E and potential ψ at a point in space, show that E = -∇ψ Homework Equations The Attempt at a Solution Does this question mean show a derivation...

Homework Statement A small, positively charged sphere is released from rest and moves directly away from a larger, positively charged sphere. During this process, the electrostatic force: a) does positive work and increases the kinetic energy of the small sphere b) does negative work and...