Electrostatics is concerned with the field and potential of stationary electrical charges and electric charge distributions. Problems are this type are almost exclusively concerned with mathematics of geometries using the inverse-square law.
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2answers
341 views
Voltage and current of positive lightning
For a physics issues investigation I chose to investigate what effects lightning could have on an aeroplane while in flight if it was struck and then go on to discuss some possible implications of ...
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votes
2answers
150 views
Effect of charges near a parallel plate capacitor
If I charged a parallel plate capacitor. And then, I insert a charged body near one of the plates.
Will there be any interactions like attraction or repulsion?
What if I disconnected the battery?
7
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1answer
351 views
Resistance between two points in an infinite metal sphere/cube
Let's imagine that we have a tridimensional metal object of infinite size, and decide to calculate the resistance between two arbitrary points. How would we go about doing this?
I have thought of two ...
2
votes
1answer
311 views
how to calculate electric relative permittivity of fluid or medium
I am confusing in calculating permittivity of the fluid. Permittivity differs from one fluid to another.
$$\varepsilon=\varepsilon_r\varepsilon_0$$
Since it is an electrical property combined with ...
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vote
1answer
23 views
Potential on a Charged Sheet
I know the field difference across a charged sheet-but what's the potential on a charged sheet? Is it just asymptotic?
If we had a thin cylindrical sheet would it be the same? Zero field inside the ...
1
vote
1answer
165 views
Finding Electric Field outside a Charged Cylinder
I'm trying to solve a problem that involves finding the electric field due to a uniformly cylinder of radius $r$, length $L$ and total charge $Q$. Well, my thought was: if I am to use Gauss' Law, I'll ...
1
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1answer
154 views
Electric field of a flat metal plate and a point particle
I'm currently studying electric potential, and I'm having trouble with one of the problems on my homework:
A) A point particle with charge $+q$ is on the x-axis at a distance $d$ from the origin, ...
1
vote
1answer
138 views
Electrostatic adhesion instead of glue. Is it possible?
I am thinking about the way to attach the printed photographs to the wall but not using the frame.
And the most interesting idea for me is the use of electrostatics.
In addition I have found the ...
1
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1answer
37 views
Effect of electric field of plasma sheaths
How will an electric fields affect the formation of plasma sheaths?
1
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1answer
166 views
What is the energy of interaction between a point charge and an infinite cylinder?
I don't remember enough from my electromagnetism course and I can't find any simple, full example on this subject.
I know, that I can consider the cylinder as a wire with the same charge density ...
0
votes
1answer
50 views
Fundamentals of electrostatics
Suppose I have a Gold Leaf Electroscope and the leaves are observed to diverge by a certain amount. Now if I send a beam of X-rays and allow it to fall upon the electroscope for a very short period of ...
0
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1answer
43 views
Potential of a Body
I have a doubt about the electric potential of a body. Well, I know that given a continuous distribution of charge we can find the potential at a point $a$ using the following relation:
...
0
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1answer
78 views
Electrostatic Potential Energy Calculation (Sign Problem)
In the derivation of electrostatic potential energy ,
how is $ds=-dr$ step justified ?
Why we use a differential position vector ? Why doesn't directly work and potential energy give the correct ...
0
votes
1answer
117 views
Applying Gauss' Law to find Electric Field
I'm in doubt in the application of Gauss' Law to find electric fields when the charge distribution is symmetric. Well, first of all: I know how to find the magnitude of the field - we just enclose the ...
0
votes
1answer
205 views
Electric field due to nonconducting sphere
For calculating electric field outside a nonconducting sphere with a hollow spherical cavity. When I use the rule (Charge density= $dQ/dV$), I don't know exactly what is $dV$, is the volume here ...
0
votes
1answer
273 views
Electric field and insulator or dielectric
I have a uniform electric field $E$ projected from left to right and I placed an insulator or dielectric right in the middle of it. To the left of the insulator, the $E$ is the original $E$. Inside ...
0
votes
1answer
156 views
Charge on capacitor plates in series combination?
Suppose 2 capacitors are connected in series, the plates connected to the battery terminals receive charges $+q$ and $-q$, and the isolated plates in the combination receive equal and opposite charges ...
0
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1answer
147 views
Force due to combination of free space and dielectric
I will make a generalized form of my question.
There are two point charges $q$, $x$ distance apart.
And there is a dielectric slab of thickness $t$ and of dielectric constant $K$.
Should the force ...
-1
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1answer
40 views
Electric dipole moment, which charge is the $q$ for?
Electric dipole moment says $p = qd$. Which charge does the $q$ equal to?
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1answer
205 views
Potential due to a spherical surface charge
The potential at the surface of an insulating sphere (radius R) is given by
$$V(R,\theta) = k \cos(3\theta)$$
where $k$ is a constant. Use separation of variables to find the potential inside the ...
-1
votes
1answer
73 views
electrical forces of two charges repelling each other
If I place two positive charges of different magnitudes on the x-axis (one at the origin, one at the some position x), as the two charges repel each other are the forces that they impart on each other ...
-1
votes
1answer
861 views
How does a Primary Charge Roller work?
I have been recently trying to get more deeply into the workings of a common laser printer.
While the basic concept seems to be fairly simple to understand I have been having trouble finding more ...
6
votes
0answers
222 views
Capacitance of this unusual capacitor
This capacitor is composed of two half spherical shelled conductors both with radius $r$. There is a very small space between the two parts seeing to that no charge will exchange between them.
...
4
votes
0answers
67 views
Electric potential of a spheroidal gaussian
I'm looking for results that compute the electrostatic potential due to a spheroidal gaussian distribution. Specifically, I'm looking for solutions of equations of the form
$$
...
3
votes
0answers
120 views
Electron hopping among molecules - Marcus equation
I'm running out of professors to talk to, and I need to clarify a couple of things for the sake of making a realistic model of electron travel through a mesh.
This is about calculations of electron ...
2
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0answers
45 views
Semi-conductors and induced charge
Can a semi-conductor ( germanium or silicon) or a semi-metal ( graphite ) carry an induced charge ?
2
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0answers
102 views
Metal sphere and charged ring
I think this is an interesting question, to which I don't really know the answer to. (Also, not a homework question.)
Say you have an uncharged metal sphere constrained to move in the z-axis. There ...
2
votes
0answers
444 views
How to calculate the electric field and potential inside a dielectric surface placed into a homogenous field
In an experiment we placed a long dielectric cylindrical shell (cylindrical tube)(with inner and outer radii r1 and r2, respectively) in a homogenous field such that its axis was orthogonal to the ...
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0answers
209 views
Electrostatic Dust Removal
I have been recently reading a paper on dust removal and I have a few basic questions regarding it.
First off, I am citing this paper - "Dust removal system with static electricity"
Basically, an ...
1
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0answers
45 views
outward pressure in an confined electron gas
Suppose i have some electrons stored in a empty shell container with a negative ion layer in the inner surface so the electrons keep bouncing inside without being able to leave the inner cavity.
I ...
1
vote
0answers
72 views
Is putting a charged balloon up to a neutral wall polarization AND temporary induction, or just polarization?
Is putting a balloon that is charged up against a wall and having it stick polarization AND charging by temporary induction, or just polarization?
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0answers
220 views
Dielectric in Parallel Plate Capacitor
Given a parallel plate capacitor of width $w$, length $l$, with a dielectric moving along the length $l$. Let the dielectric be from $x$ onwards.
The capacitance will be $\frac{w \epsilon_0}{d} ...
0
votes
0answers
20 views
How the value of permitivity of free space is determined?
when electric charges are placed on the medium then force of interaction between them decreases. We say this factor permitivity of the medium. The force of interaction between the charges is max if ...
0
votes
0answers
44 views
The electrical field of a conductive sphere containing a charge - gounded vs not grounded
Let's suppose we have a sphere but unlike theoretical ones it'll has have some thickness say $\Delta r$ and inner radius $R$. What I was wondering about is how will it behave if we place some charge ...
0
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0answers
56 views
Curie's principle in electromagnetic field theory
I am looking for some explanation and if possible also some references about the applications of Curie's principle in electromagnetic field Theory, precisely in the computation of magnetic (resp. ...
0
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0answers
37 views
Charge residing on an overpolished surface
I had very well read that when charge is stored on a rough surface, the leakage is very high from the pointed tips of such surfaces, by a phenomenon called action of points. But now, I've come to know ...
0
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0answers
63 views
Finding final charge distribution on capacitors on grounding
I am trying to solve the following problem on capacitors:
Here's the circuit
I have to find the total energy loss when all three switches are closed, and subsequent equilibrium attained.
I had ...
0
votes
0answers
75 views
Electric potential due to an infinite polarized sheet
I have an infinite plane (no thickness) with a uniform dipole density $\mathbf p = p \mathbf n$, with $\mathbf n$ being the normal to the plane. So the surface charge density is $\sigma = \mathbf p ...
0
votes
0answers
164 views
Induced surface charge of conducting sphere, and energy?
Find the induced surface charge on a conducting grounded sphere as a function of the polar angle. The hint given is to integrate this charge density over the sphere to find the total induced charge.
...
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0answers
65 views
Electric field singularity
What's a general proof for the log-singularity of electric field near the edge of a uniformly charged surface?
0
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0answers
34 views
Working out the electron mobility from the transfer rate (1/s)
I have an electric field value for a uniform structure through which an electron travels. Given that I've calculated a transfer rate (frequency) for the electron when it goes from one molecule to the ...
0
votes
0answers
111 views
Charging a metal plate
I am supposed to find a way to charge a metal plate with a defined charge ( in nanocoulomb) and it must have a + charge so basically i want to know if this way is correct and applicable, and if there ...
0
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0answers
74 views
What happens when I bring a sphere of positive charge near to the sphere of negative charge?
I am wondering what would be the charge density distribution when I bring a sphere of positive charge $Q$ near to the sphere of negative charge? What would be the charge distribution inside the sphere ...
0
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0answers
107 views
How do I find the force on the charged sphere due to a dipole sitting inside?
I have a dipole sitting inside a charged sphere i.e. at the centre of the sphere. As far as I can see the force on the Dipole is zero because the external electric field on the dipole at $r=0$ is $0$. ...
0
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0answers
136 views
A crazy problem
Easy
Consider the following figure
Each red point is a particle of a known mass that carries charge Q/2 and connected to a the box by a thread of known length. This problem can be solved easily to ...
0
votes
0answers
68 views
In a region free of charges, an external charge can not be in stable equilibrium
How to prove using Gauss' theorem that in a region free of charges, an external charge can not be in stable equilibrium due to electrostatics forces alone ?
I tried like this: Using Gauss' law ...
0
votes
0answers
52 views
Question on conduction
I already know that a charged polyethylene plastic (done by rubbing it with paper) can be used to attract a cardboard. Now, can I 'charge' the cardboard by touching it with the plastic? Supposedly, ...
