Electrostatic Definition and 857 Threads

Hello, I have a particle at point A with charge ##q_A##, and an unmovable sphere of radius ##R_B## at point B with a volumic charge density ##\rho##. The distance from particle A to the centre of the sphere in B is ##r##. Both objects have opposed charges, so, the particle in A, initially at...

I tried just calculating the force with Coulomb's law, then calculating the forces for each vector individually and adding, but I got it wrong both ways

Hey guys! I'm having trouble with the solution that I arrived at. Through boundary conditions I'm able to determine ##\vec{D}## as $$\vec{D}=-\frac{4Q}{R_0^2}\hat{e_z}$$ (In CGS units) Trough that I'm able to get the electric field as $$\vec{E}=-\frac{1}{\epsilon(r)}\frac{4Q}{R_0^2}\hat{e_z}$$...

Electrostatic energy involves a volume integral and a surface integral The question is how to apply this formula to a finite space in which case the 1st term (surface integral) won't vanish. Let's apply to a capacitor and enclose the capacitor by a closed surface. Calculate the energy integral...

I tried to do a Euler Lagrange equation to our Lagrangian: $$\frac{S_\text{eff}}{T}=\int d^6x\left[(\nabla \phi)^2+(\nabla \sigma)^2+\lambda\sigma (\nabla \phi)^2\right]+\frac{S_{p.p}}{T}$$ and then I would like to solve the equation using perturbation theory when ##Q## or somehow...

I used the concept of electrostatic induction, which would cause the charges in metal ball near the ebonite rod to have +ve charges on end next to rod and a -ve charge on the end touching the other ball. What confuses me is how charges separate on the second ball. The only way these balls can...

I am trying to check if an expression is dimensionless. If it is, then I have done things correctly. However, I am stuck on how to deal with a (Debye^2) term. How can I break it down to find out if it cancels out with the other units I have left? I know this is probably a trivial question...

We know that both the interior and the surface of an electrostatically balanced conductor are equipotential. My question is if when we approach the loaded objects, the surface of the conductor will continue to be an equipotential. If not, then there could be a field line that left the region...

So it seems the typical way to approach this problem is to consider the sphere when it has charge q and radius r. With uniform charge density ##\rho##, this becomes ##q = 4/3 \pi r^3 \rho## and so ##dq = 4 \pi r^2 dr \rho##. Using our expression for the potential outside of the sphere, we find...

Summary:: If you rub against each other two sheets of paper, one of which contains text, they become electrified. The electrical pattern that is formed on the clear sheet may be analyzed later to restore the text, depending on the way the text was created. Propose and build a setup to recover...

I have noticed that F = -dU/dx in gravitation gives the attractive force experienced by both bodies. For capacitors, does F = -dU/dx give the force experienced by each capacitor?

We all know that Poissson's equation in electrostatic is: $$\nabla^2\phi=-\frac{\rho}{\epsilon_0}$$ My question is: why the solution, let's say for 1D, is not just double integral as follows: $$\phi=\iint -\frac{\rho}{\epsilon_0} d^2x$$ which gives x square relation. But the actual solution...

Each different boundary condition means a different charge configuration, how can this problem be solved using superposition?

Hello everyone! I've tried everything but the equation (3) in "Deflection of electrons in electrostatic field" is impossible. Can someone at least hint me to a a way the composed it ?

If we have a small dielectric sphere and a point charge, they will experience an attractive force due to electrostatic induction. (From the elongation/rotation of charges bound to individual atoms). Likewise, if we have a small metallic sphere and a point charge, they will experience an...

Why was that concept necessary ?, I know there's also a gravitational equivalent of this concept I couldn't find anything on google Thanks Daniel

I’m having A bit of confusion regarding this. In a plasma by turning on an electric field ,wouldn’t this cause an oscillation of the electrons about the ions,effectively a oscillating dipole thus inducing a magnetic field, by amperes law? My text (plasma physics by F.Chen )has curlE =0 I’m not...

Could somebody check my solution? I want to know is it correct.

I know the energy is ##\frac{q²}{ 8 \pi \epsilon_{0}}( \frac{1}{a} - \frac{1}{b})##, but I can't get this result using the second equation. What I did: ##W = \frac{1}{2} \int \rho V d \tau ## ##\rho = \frac{q}{ \frac{4}{3} \pi r³}, a < r < b ## ##V = \frac{q}{4 \pi \epsilon_{0} r}## ## W =...

As I understand potential difference is the reason of current. Does it mean that the electrostatic force creates current?

An object on the surface of the ground does not penetrate the ground. How much is this because of the electrostatic force between the particles constituting the ground and the object, and thereby maintaining their integrity? And, how much is it because of the materiality of the mass of the...

In 2D modules, the 3rd direction isn't shown in model settings. What assumptions are made regarding electrostatics 2D modules? For example, how is a 2D Poisson's equation with point sources solved? Is it based on a 1/r potential or a log potential?

Assuming we have an infinite plane capacitor,where the upper plate is charged positively and the bottom layer is charged negatively. Now we know the field outside the capacitor is zero so we can't tell if the positive charge is on the upper plate or the lower plate. But, if we place it inside...

I have not clear how to solve this problem. Here it is my attempt at a solution: Let the charge at ##-a## be the number one and the one at ##+a## the number two. the potential energy of the punctual charge ##-Q## due to each charge +Q will be then ##E_{pi}=-k \frac{Q^2}{r_i}##, whit ##r_i## the...

My work is in the following pdf file:

What is the electrostatic field of a non-conductive sphere (it's radius is R) which has a density charge distribution inside? ρ0 and R are parameters. I started solving this with Gauss's law: then: Solving the integral: This means the electrostatic field of the sphere in r is: Can you...

I set the electrostatic force exerted by the object at (0,0) and (3,0) equal to each other, dividing out k and q2. I was left with q1/d^2 for both terms and substituted in the given charges for each object. I then replaced d^2 for the object at (0,0) with “x^2” and d^2 for the object at (3,0)...

The correct answer is B, but I am not sure why. I have a few confusions regarding this problem. First of all, I had thought that we cannot use Gauss' Law to determine the flux through a SIDE of a cube since Gauss' Law only works for SURFACES. How can we determine how an electric field pierces a...

"When electrified rods are brought near light objects, a similar effect takes place. The rods induce opposite charges on the near surfaces of the objects and similar charges move to the farther side of the object." -from a high school physics book. NCERT Class 12th part 1 to be precise. can...

I assumed a uniform distribution of charge within the droplet such that ##E = \frac{q}{4\pi\epsilon_{0}r^{2}}## at the outside surface. I then said that the pressure acting at the surface would be the force on a charge element ##dq## within an area ##dA## on the surface, divided by the area...

The load system formed by the point load and the load distribution generates two regions in space corresponding to r<1m and r>1m, i.e. inside and outside the sphere. Given the symmetry of the distribution, by means of the Gaussian theorem we can find the modulus of the field at a distance r from...

Given here is that by geometry r1^2 =r^2 +a^2 - 2ar*cos(theta) But if we try to do vector addition then since direction of dipole is upwards then it should be r^2 =r1^2 +a^2 + 2ar1*cos(alpha) Where alpha is the angle between a and r1. I Don,'t understand how they get it by geometry

The equation that we saw in class is for a continuous charge distribution, I think that for this exercise I need to treat the system as a discrete charge distribution but I'm not sure. Also, I don't know how I can calculate the intensity of the electric field needed to move this charge.

I was thinking that we can equate the electrostatic potential energy and the spring energy (as the force is similar to that of a spring so energy will also be 1/2kx^2 ) but i am not getting the correct ans but by equating the net force on one charge to kr i am getting the correct ans can...

the image is given here along with some numerical information: Now I know that the formula for the electric field in a capacitor is given as: $$E = \frac{V}{d}$$ which I can use to obtain the three following fomulas: $$E_1 = \frac{V_1}{d}$$ $$E_2 = \frac{V_2}{d}$$ $$E_3 = \frac{V_3}{d}$$ where...

I tried to use ##W = ε_0/2 \int E^2d\tau## for all space. So I find that ##E = \frac{(R^3 - b^3)\rho}{3ε_0r^2}## where ##\rho## is the charge denisty. So from here when I plug the equation I get something like $$W = \frac{(R^3 - b^3)^2\rho^2 4 \ pi}{18ε_0} \int_{?}^{\inf}1/r^2dr$$ Is this...

Hello to everyone. The question or debate here is how you obtain the commonly known equation of dipole electric moment: from the electrostatic potential equation for a multipole of order n: I understand it is related with Dirac delta functions but a step by step solution might be helpful.Thank...

Hi! I need help with this problem. I tried to solve it by saying that it would be the same as the field of a the spherical shell alone plus the field of a point charge -q at A or B. For the field of the spherical shell I got ##E_1=\frac{q}{a\pi\epsilon_0 R^2}=\frac{\sigma}{\epsilon_0}## and for...

Hi! I need help with this problem. When the outer shell is grouded, its potential goes to zero, ##V_2=0## and so does it charge, right? ##-Q=0##. So the field would be the one produced by the inner shell ##E=\frac{Q}{4\pi\epsilon_0 R_1^2}##. When the inner shell is grounded, I think that...

Except for railguns every space launch method we have (at least partially) built has been based on the rocket engine. But with the Earth Moon system we have an opportunity to use another method. Put a 6GeV ion beam accelerator on the Moon, and transfer 400000C of charge to the Earth. This sets...

This is Jackson's 3rd edition 1.12 problem. So, for both ## \phi ## and ## \phi' ##, I started from Green's second identity: ## \int_V ( \phi \nabla^2 \phi' - \phi' \nabla^2 \phi )dV = \int_S ( \phi \frac {\partial \phi'} {\partial n} - \phi' \frac {\partial \phi} {\partial n} ) dS ## And...

In Physics/Electrostatics textbook, I am in a situation where we have to find the electric field at a point inside the volume charge distribution. In Cartesian coordinates, we can't do it the usual way because of the integrand singularity. So we use the three dimensional improper integral...

How to calculate the eletrostatic potential on a 3d object, for example a ring, if it is charger with some "Q" charge what is the potential on the surface of the ring?And how do i calculate it based on the charge of the ring?

Let ##Q## - charge of one of conductor, ##\phi_1## --- potential of charged conductor, ##\phi_2## --- potential of uncharged conductor. For the charged conductor: \begin{equation} \phi_1 = D_{11}Q , \end{equation} for uncharged conductor: \begin{equation} \phi_2 = D_{21}Q \end{equation}

I have a proton and an electron at a certain distance from it. The proton exerts an electrostatic force on the electron. I then neutralize the proton's charge by firing another electron at it from behind. How long does it take for the first electron to sense the change?

I am trying some projects that involve building some very simple electrostatic motors. I attached below figures of the kind of electrostatic motors I am trying to make. What I can't figure out is what kind of high-voltage power supply I should use, presumably 1000 to 10,000 volts is what these...

What is true is that the field due to the point charge outside of the conductor will not be able to penetrate the shell i.e. there will be no field due to the external point charge anywhere within the conductor nor in the cavity: the field will be **killed off*& by the charges on the outer...

How will the repulsion of electrons occur in the simulation hypothesis? The electrons will also create electrostatic fields around yourself ?

The electric field due to a dipole distribution in volume ##V'## can be viewed as electric field due to a volume charge distribution in ##V'## plus electric field due to a surface charge distribution in boundary of ##V'##. ##\displaystyle\mathbf{E}=\int_{V'} \dfrac{\rho...

Why there is not voltage or current just for 1ms if I connect a multimeter ground to the negative terminal of a DC power supply or charged capacitor? Why electrons in measure lead and DMM device cannot sense a bulk of electrons (or lack of it)? I tried with an 5kV DC power supply too. In an...