Electrostatics is concerned with the electrical fields and scalar potentials of stationary electrical charges and charge distributions. Use this for questions about electromagnetic situations in which currents and magnetic fields are absent, otherwise use [tag:electromagnetism] and/or ...

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Dipole moment of a single point charge

Kindly refer to "MULTIPOLE EXPANSION" section of Introduction to electrodynamics by Griffiths(Chapter 3). Let us first discuss about why multipole expansion is needed. As far as I understand, if we ...
12
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7answers
827 views

Why is capacitance defined as charge divided by voltage?

I understand that capacitance is the ability of a body to store an electrical charge and the formula is $C=\frac{Q}{V}$. What I don't understand, however, is why it is defined as coulomb per volt. Of ...
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1answer
30 views

While deriving Coulomb's Law from Gauss' Law, the power of 'r' comes out to be exactly 2 while experiment shows that it differs about 10^(-16). Why?

While deriving Coulomb's Law from Gauss' Law, the power of 'r' comes out to be exactly 2 while experiment shows that it differs about 10^(-16). Why is it so? I'm referring to the book 'Physics by ...
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1answer
40 views

Coulomb's law and its application [on hold]

I just read that Coulomb*s Law describes (a) the forces that bind atoms together to form molecules (b) the forces that bind molecules together to form solids. My question is Do a proton share ...
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2answers
155 views

Does charge of a metal charged by induction determine by which ends of the metal is grounded to?

Does charge of a metal charged by induction determine by which part of the metal is ground to? I draw a diagram to make it simple to understand: Right diagram: When ground is touched with the ...
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2answers
39 views

Calculating the surface integral over a charged box

In a question that I'm trying to solve, we're told that there is a box with dimensions 20cm long, 4cm high, and 3cm deep. we're given that the electric field on every surface of the box is pointing ...
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0answers
30 views

Calculation of charged sphere distribution near a wall in Cartesian coordinates

I am following a similar derivation as found in the beginning of this paper "Quantitative aspects of the growth of (charged) silica spheres" by A.P. Philipse. This paper calculates the growth of a ...
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1answer
18 views

Energy (voltage) correction on energy level between metallic electrodes with dielectric and accounting for work function difference

My goal is to understand how to correct for the field drop and the work function difference when performing electrical measurements on a certain energy level of a sandwiched system. The situation is ...
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1answer
30 views

Understanding electric potential in the context of gravitational potential?

I'm trying to understand the concept of electric potential and the significance of an electric field being related to the gradient/derivative of an electric potential. I found this question that ...
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1answer
23 views

electric charges on the surface and inside a charged body [on hold]

There is a hollow object (for example an inflated balloon.it is charged. where will the charges reside? Inside the balloon or on the surface of it? Why what will be the case of a solid sphere which is ...
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1answer
312 views

Why does a point charge generate an electric field and why is an electric field represented by this formula?

Why does a point charge generate an electric field and why is an electric field represented by this formula $$E ~=~ \frac{q}{4 \pi \epsilon r^2},$$ where $\epsilon$ is permittivity of free space ...
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0answers
33 views

Self enery of a sphere [on hold]

If we have a sphere of radius 2R in which there is a cavity of radius R with concentric centre . Now we have to find self energy. I searched and got 3 methods : 1) U'' + U' + U* = U In this we ...
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2answers
18 views

Net Electrical Force

If a metal is insulated from earth and if a charged object is held near one end of it but not touched , will the net force acting on the metal be zero ?
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7answers
239 views
+50

Is the electric field of a volume charge distribution well defined?

Consider a volume charge distribution $\rho({\bf r'})$. The electric field at ${\bf r}$ is $${\bf E}({\bf r})=\iiint\frac{1}{4\pi\epsilon_0}\frac{\rho({\bf r'})}{R^2}\hat{\bf R}\, \mathrm d^3{\bf ...
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2answers
35 views

I don't get the idea of potential in a capacitor

First off, what is meant by the potential of the conductors? Also potential difference between the two conductors is a function of distance from either right? Then why does it have an exact value. For ...
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0answers
17 views

Does a positive electric charge moves when it is placed inside a hollow conductor, but not in the center?

Electric Field inside a hollow conductor is zero. But what happens to a positive electric charge put inside.
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2answers
44 views

Can a grounded spherical shell have a charge?

Can a grounded spherical shell lying inside another bigger non-grounded shell have charge on it? If yes then why? Won't the charge on the grounded conductor flow to the ground?
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0answers
26 views

Gauss's law in three parallel plates

There are three identical conducting plates with large surface area kept parallel to each other. The leftmost plate is given a charge Q , the rightmost a charge -2Q and the middle one remains neutral ...
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0answers
30 views

Electric field and potential at a point [on hold]

Consider an infinite rod with charge density = Ax (where A is constant). Given that electric field at point S on y-axis is E, Find electric field and potential at point P. a,d are constants. I tried ...
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0answers
29 views

Electron travel speed in spinning object [on hold]

My question is in the hypothetical circumstance that you could spin a disk or something close to the speed of light how would that effect the travel of electrons through the material. Picture a circle ...
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4answers
6k views

Potential difference between point on surface and point on axis of uniformly charged cylinder

Question: Charge is uniformly distributed with charge density $ρ$ inside a very long cylinder of radius $R$. Find the potential difference between the surface and the axis of the cylinder. Express ...
0
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1answer
11 views

How does electric charge flow in the typical experiment of scuffing your shoes across the carpet?

I'm trying to understand the flow of electric charge. I have read about the triboelectric series, but I do not know where the rubber soles of shoes and carpet reside to know whether the shoes acquire ...
2
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3answers
197 views

Static electricty and fields inside of the conductor?

I have a few related questions about static electricity and conductors. 1. when we say static electric field inside a conductor is zero, let us take an example of two concentric conductors, outer one ...
3
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2answers
48 views

Electric field inside a material

I was thinking about the polarisation, and how the electric field behaves inside the material of permittivity greater than one. I think to have understood what happens to D and P, but is not clear ...
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1answer
16 views

Surface charge distribution on a conductor derived by method of images techniques

Kindly refer to "The classic image problem" of "THE METHOD OF IMAGES" of Introduction to electrodynamics book by Griffiths (Chapter 3). A point charge is placed at (0,0,d) on the z axis. The XY plane ...
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2answers
402 views

Capacitors in a series circuit with dielectric

When a dielectric slab is inserted between the plates of one of the two identical capacitors in Fig. 25-23, do the following properties of that capacitor increase, decrease, or remain the same: (a) ...
3
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1answer
33 views

Gauss law and electrostatic induction. Concentric spheres

Imagine you have hollow concentric spheres A and B with radius a and b (b>a), respectively. If A is a conductor and B has a certain density charge, I´ve been taught that B will induce some net charge ...
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1answer
25 views

Electric potential and work

A unit positive charge $q$ is placed in an electric field caused due to a positive charge $Q$. $q$ experiences force of repulsion $F_R$. We apply an external force (FEXT) opposite to $F_R$. The ...
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0answers
19 views

Charged metal sphere- electric potential [duplicate]

Why is the electric potential on the surface of a charged metal sphere always constant?
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2answers
64 views

Whats the meaning of this equation relating electric field and potential energy?

My electrodynamics teacher was explaining that it is required to apply some energy (or do some work) on charges in order to arrange them in space. When he stated an example about energy in a capacitor ...
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4answers
11k views

Why is the electric field perpendicular to every point on the surface of a conductor?

I am reading Berkeley Physics Course, Volume 2 (Electricity and Magnetism by Edward M. Purcell). I am in chapter $3$, page $92$, and the book discusses conductors. The following is from the book: ...
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0answers
27 views

Electric potential inside a conductor inside another conductor [on hold]

Suppose there is a neutral hollow conductor body $B_2$ and there is another hollow conductor $B_1$ inside $B_2$ . Let there be a charge $q$ on $B_1$ . Let the potential inside $B_2$ but outside $B_1$ ...
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0answers
26 views

Fourier Transform point force on a half-space [migrated]

I have to calculate the following Inverse Fourier-Transform, which describe the potential function for a point force on a half-space: ...
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0answers
14 views

electrostatic seperator build questions [on hold]

i am building an electrostatic seperator for plant material. the two materials i am trying to seperate have a negative charge but one responds a lot more to positve charges so i feel there will still ...
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1answer
159 views

Two concentric conducting shells connected by wire with modified Coulomb law?

This question is related to this one, but is a bit different. Consider two concentric and conducting spherical shells connected by a wire. Inner shell has radius $b$ and (unknown) charge $q_b$ while ...
1
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1answer
266 views

Force and Energy of interaction of conducting sphere and point charge

A completely isolated neutral conducting sphere of radius $R$ is kept such that its center is at a distance of $r\left(>R\right)$ from a point charge $+Q$. How can I find the force of ...
1
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1answer
67 views

Electric Flux is zero

When is the Electric Flux zero through a closed surface? I know that if number of field lines entering is equal to leaving then it is true. Which I think is always true for a closed surface. So can ...
4
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4answers
340 views

Electric field on the surface of a charged sphere

We know that the electric field for a point charge is $$ E = \frac{KQ}{R^2}. $$ If $R$, i.e. distance from the electric field producer to the point where we want to find the electric field becomes ...
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votes
1answer
40 views

electrostatics and elecrtic field [closed]

two opposite charges are placed and thee electric lines of forces are drawn if the angle made by the tangent at the initial point of one charge is 'a'then find the angle made by the line of force that ...
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2answers
42 views

Electric Field Vector on an insulating solid ball

An insulating solid ball with radius $R$ has a uniform charge density $ρ$. Find the electric field vector inside and outside of the ball if it has dielectric constant $K$. Normally, I'd treat ...
4
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3answers
59 views

Spherical Shell with Electric Field Zero Everywhere Inside It

If an isolated, charged spherical shell has a uniform charge distribution, the electric field everywhere inside it is 0, by Gauss' Law. Is the converse true? That is, given an isolated, charged ...
0
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1answer
19 views

Force on a charged conducting sphere due to a uniform electric field

If a charged conducting sphere is placed in a uniform electric field , will the force on it be simply qE ? I know that the electric field lines enter a conductor perpendicularly so does this have any ...
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2answers
166 views

How is Capacitance affected by a seperation distance and with or without a battery?

The questions specifically says this : A parallel-plate capacitor initially has capacitance $C$. The distance between the plates is then doubled, with a $9.0V$ battery connected. The battery is then ...
0
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2answers
30 views

Electric potential inside a shell

Inside a shell, electric field is zero. Then does it have a constant electric potential inside the shell? If $V=\dfrac Ed$, then since field is zero, potential should also have been zero. Please ...
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0answers
16 views

Why will the force of repulsion decrease in two conducting charged spheres when kept close to each other? [closed]

The force of repulsion between two point charges is $F$ when these are at a distance 0.1 Metre. Now the point charges are replaces conducting spheres of radii 5cm each, having the same charge as point ...
5
votes
6answers
2k views

What is the origin of the Dirac delta term in the dipole electric field?

I am a bit lost how one has deduced the formula for electric field with electric dipole because of some inconsistency between different sources. The Wikipedia article contains a delta function in the ...
2
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2answers
2k views

The total energy of an electrostatic system

My problem is from Griffiths Introduction to Electrodynamics, Fourth Edition, p.112 Problem 2.60 (not homework): A point charge $q$ is at the center of an uncharged spherical conducting shell, ...
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0answers
16 views

Wearing a metal had does, or does not, increase your chance of being struck by lightning?

Prompted by this video My view is that it makes no difference as to the conductivity of the head or the field strength around the head during a thunderstorm. OTOH, would an insulating hat reduce the ...
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0answers
21 views

How is corona discharge different from regular electricity ? [on hold]

Since corona discharge is a electrical discharge is it any different from regular electrcity in terms of its ability to travel through wires, create magnetic fields , etc.