Electrostatic Definition and 857 Threads

Homework Statement When books of elctromagnetism talk about Electrostatic equilibrium，they say electric charges will keep moving if electric field in the conductor doesn't equal to zero utill it does.However,what if there are no excess free charges in the area where that doesn't equal to...

Homework Statement a) Calculate the electrostatic force on an uniformly charged rod of length 2L and charge q, which lies along the axis of an uniformly charged ring of radius R and charge q'. The centers of the charged rod and the rings are displaced at a distance z= z0. b)Show that if z0 >>...

Homework Statement There are four charges, each with a magnitude of 2.1 µC. Two are positive and two are negative. The charges are fixed to the corners of a 0.25 m square, one to a corner, in such a way that the net force on any charge is directed toward the center of the square. Find the...

Homework Statement Homework Equations F = k*Q1*Q2/r^2 The Attempt at a Solution My work is E(x) = (k*Q1)/(x^2) - (k*Q2)/((L-x)^2) Find derivative and set E(x) = 0. But I get a non real answer. Am I doing this completely wrong here? I was going to solve for x here.

When an electron and a positron annihilate, they typically produce two gamma rays, each of energy mc^2 plus whatever kinetic energy available before annihilation. I was recently told that it is an experimental fact that the electrostatic energy between the electron and the positron does NOT...

So, when I was learning about static electricity and induction and conduction, there were several labs done where a pith ball or electroscope could be manipulated through induction when a charged object was placed near it. In the case of the little pith ball, a negatively charged piece of PVC...

Homework Statement Two dust particles are separated by 0.01m and of the same mass and charge, find the total potential energyHomework Equations E_{el}=k\frac{q_1 q_2}{r} E_{grav}=-G\frac{m_1 m_2}{r} r=0.01 m, q_1=q_2=1.1201\times10^{-18} C m_1=m_2=13\times10^{-9} kg Where G and k are the...

Homework Statement I am confused b/w two questions: 1) The mass M of a planet Earth is uniformly distributed over a spherical volume of radius R. Find and expression for the energy needed to disassemble the planet against the gravitational pull amongst its constituent particles. 2) A metal...

Homework Statement In fair weather, over flat ground, there is a downward electric field of about 150 N/C. A) assume that the Earth is a conducting sphere with charge on its surface. If the electric field just outside is 150 N/C pointing radially inwards, calculate the total charge on the...

A conductive plate with no initial charge is put between two identical positevily charged plates. Is it possible that the plate which is put between those two plates configures a situation where the net force acting upon each plate is zero? (the third plate could have different dimensions then...

Homework Statement Measurements show that a honeybee in active flight can acquire an electrostatic charge on the order of 90.9 pC. a)How many electrons much be transferred to produce this charge? Ne =5.67*10^8 b) Supposing two bees, both with this charge, are separated by a distance of 14 cm...

Homework Statement Two small objects, A and B, are fixed in place and separated by 2.46 cm in a vacuum. Object A has a charge of +1.18C, and object B has a charge of -0.937C. How many electrons must be removed from A and put onto B to make the electrostatic force that acts on each object an...

Homework Statement Of the charge 'Q' initially on a tiny sphere, a portion q is to be transferred to a second, nearby sphere. Both spheres can be treated as particles. For what value of q/Q will the electrostatic force between the two spheres be maximized? The Attempt at a Solution The...

The question is like this: 8 charges of magnitude q and different sighs are placed at corners of a cube of side a. Find the work done in taking them far away from each other. Homework Equations U = kq1q2/r W = ΔU The Attempt at a Solution First i found out the potential energy...

Homework Statement Suppose that two balls of mass 1.5x10-4kg each carry equal charges and are suspended by identical threads of length 11cm anchored 28cm apart. If each thread makes an angle of 20 degrees with the vertical, what is the charge on each ball? Homework Equations F=kq2/r2The...

A proton is in a vacuum near the surface of Earth. Where should a second proton be placed so that the electrostatic force it exerts on the first proton balances the weight of the first proton? F = (k×Abs[q1]×Abs[q2]) / r^2 k = 8.99×10^9 Nm^2/C^2

Hi, I am trying to do the multipole expansion of a point charge away from the origin, I can't understand Legendre polynomials so want to do it in Cartesian but when I try to Taylor expand the \left|\frac{1}{\vec{r}-\vec{r'}}\right| I am not sure how to handle the modulus. Any help...

Homework Statement During a collision between two initially uncharged polystyrene balls of radius 2 mm, some electrons are transferred from one of the balls to the other. In what direction does the resulting electrostatic force between the balls act? The magnitude of the force between the...

Homework Statement Here is the problem : http://i1200.photobucket.com/albums/bb327/loba333/untitled.jpg ill write it out again aswell A particle with charge +9 μC is placed at the origin, and another particle of charge –2 μC is at x = L. At what two points is the net electrostatic potential...

Homework Statement A mad scientist is designing a trap for intruders that will lift them up into the air and hold them helpless. The device consists of an equilateral triangle, 10.0 meters to a side, embedded in his floor. When he flips a switch, the corners of the triangle will be charged...

Homework Statement The attractive electrostatic force between the point charges 8.12×10−6C and Q has a magnitude of 0.670N when the separation between the charges is 7.26m. Find the sign and magnitude of the charge Q. (this is a direct cut and paste) Homework Equations...

At equilibrium, a conducting object will have no electric field, current or excess charge in its interior. There's a fairly simple derivation for how an initial (non-equilibrium) interior charge density d0 falls to zero exponentially with time t when the conductor approaches equilibrium. For a...

Hi all Suppose we have a conducting shell (which is not necessarily a sphere) and no electric charge inside. Is the electrostatic field inside the conducting shell always zero? (even if there is some charges outside the shell) What if the shell is grounded? If the answer is yes, how it...

What comprises the electrostatic field? Electromagnetic radiation is made of photons, but what about the electrostatic field? Two static charges exert forces on one another, through their E-fields, presumably through photon exchanges. I am having trouble forming an idea of what an...

Everyone knows that the potential difference between two points 1 and 2 is given by \int_{1}^{2}{\vec{E}}\cdot d\vec{l}. My question is that can we calculate the potential difference between two point charges by this formula? Say, one of them is +ve charge and the other is a -ve charge...

Homework Statement Well we just learned about Coulomb's Law today but there is something that is bothering me. According to Coulomb's Law the magnitude of the force of attraction between a charged and neutral object is 0. However, the Law of Electrostatics states that a charged and neutral...

Hello, I am trying to fully wrap my head around signal shielding so as to take it from the trial-and-error domain to the theoretical design domain. The problem is that I am stuck on one of the very basic and fundamental principles of shielding - the floating conductor as an electrostatic...

There is known effect when electric field bends water stream: http://www.school-for-champions.com/science/static_induction.htm" Does that mean that moving water inversely affect electric field?If yes,could we make electric generator in which moving water would affect electric field and...

Your Open QuestionShow me another » How to increase electrostatic force? I am from grinding wheel industry, on one process grains are placed on the belt conveyor. Below this conveyor aluminum sheet is connected with 11 KV power supply. Then backing disc is brought near the conveyor. then...

Homework Statement "In class we calculated the electrostatic self energy of a uniform density sphere of charge, i.e., the work required to assemble the sphere from "infinite dispersal." Along the same lines, calculate the electrostatic self energy of a spherical shell of charge, of negligible...

Suppose we have three charged particles arranged in a line, the first one being negative, the second being positive, and the third being negative. If we want to find the net force on the third particle, we sum the force from the second particle on the third and the force from the first...

Homework Statement I'm looking at Y.K.Lim's Problems and solutions in Electromagnetism and there's one thing that's confusing me: [PLAIN]http://img545.imageshack.us/img545/2218/capturegb.png Homework Equations Where does the square in r comes from? When in the beginning it says...

I hace read in Electrodynamics from griffiths chapter 2, that, whenever acavity is inside an spherical conductor, for the outside it acts as if there was a point cherge at the center... But what if thew conductor has another shape, for example a revolution ellipsoid...?? how do you deal with...

Assume that you have two protons accelerated in opposite directions within a cyclotron. As they approach the speed of light their masses increase. At what proportion of the speed of light will their gravitational attraction (due to their increased mass) equal their electrostatic repulsion ?

Thinking in terms of electric circuits and electrostatic potential I understand how an electric current arises as manifestation of a difference in potential. How does this work at a more microscopic level? I.e. how does an electron know what potential it's environment is at? E.g.: If I...

Electrostatic Forcce :( Homework Statement In Fig. 21-26, particle 1 of charge q1 = +1.4 µC and particle 2 of charge q2 = -4.2 µC, are held at separation L = 12 cm 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...

Homework Statement Identical isolated conducting spheres 1 and 2 have equal charges and are separated by a distance that is large compared with their diameters (Fig. 21-22a). The magnitude of the electrostatic force acting on sphere 2 due to sphere 1 is F = 6.5 N. Suppose now that a third...

Homework Statement How far must two protons be placed on the Earth’s surface for there to be an electrostatic force between them equal to the weight of one of the protons? Homework Equations The Attempt at a Solution

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...