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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How do I account for presence of a dielectric medium while calculating potential due to a point charge?

I am not sure but I believe that the potential due to a point charge will reduce if the entire setup is kept in a dielectric medium. How do I account for it in deriving the potential?
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11 views

On rubbing two bodies together, can we predict the nature of charge on each of them? [duplicate]

Is it possible to know, without actual experimentation, which of the two bodies will get positively charged or negatively charged after being rubbed against each other?
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1answer
60 views

Energy stored in electric field [duplicate]

I know that energy stored in electric field / unit volume = $\frac{1}{2} \epsilon\,E^2$. so can I say that for any configuration calculating $\int \frac{1}{2} \epsilon\, E^2 \,d^3r$ over whole space ...
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1answer
22 views

Electrostatics - System of parallel plates

For a system of $n$ parallel metal plates bearing charges $q_1, q_2,\dots, q_n$, why it is so that the facing surfaces of the plates bear equal and opposite charges? How do we prove that?
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29 views

How do we calculate electric field on the axis of a disc using gauss law and the concept of solid angle?

We can easily find the electric field at the axis of the disc by considering a differential ring and then integrating it to form a disc, but I was searching for rather a bit simplified proof using ...
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1answer
38 views

Gauss law in dielectrics

How shall we apply Gauss's law for a space such that the volume enclosed by the Gaussian surface have 2 or more mediums with different dielectric constants, such that equal or more than two ...
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3answers
75 views

What is the maximum reach distance of electric field? [duplicate]

if i charge small object by removing electrons and put that object in the middle of huge vacuum chamber (million of light years in size) does the electric field lines of that charged object still be ...
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2answers
105 views

Relation between Electric field and potential

I am unable to understand from this - sign comes. Which step I have done wrong?
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1answer
58 views

Confusion regarding gauss law

Gauss law states that flux due to net electric field on a Gaussian surface is charge enclosed/permittivity. Lets take a spherical Gaussian surface with +q charge at centre. We can simply calculate the ...
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1answer
35 views

Inconsistency in solving energy in free space given electric potential

So we have the equation $$ W= \frac{1}{2} \int_{volume} \rho_v V\,dv$$ and then after applying a vector identity which is $$\nabla \cdot (V\vec{D})=V(\nabla\cdot \vec{D})+\vec{D}\cdot (\nabla ...
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1answer
46 views

What role does the center of mass play in this situation? (electric potential)

Four masses $10\ \mathrm{g}$ each are tied together by $10\ \mathrm{cm}$ strings to make a square as shown. Two of the masses carry a charge of $2\ \mathrm{\mu C}$. The string between the two ...
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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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Find the force that tries to rip apart a conducting shell into two halves about its equator when kept in an uniform electric field of magnitude E

The conducting spherical shell will be affected by the electric field and one can expect induced charges on the two hemispheres if visualized as cut by an equatorial plane. The induced charges ...
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2answers
22 views

Electric charge and and cylindre

An electric charge is distributed with a uniform volume density $\rho$ in a cylindre with a radius $R$ and an infinite length. Our professor said the following: By symetry the electric field is ...
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1answer
34 views

Does is make sense to speak of the value of electric field at points containing continuous charge distribution?

Before getting into the question, here are some remarks: 1)Given a single point charge, the value of electric field at the position of the charge is singular/undefined, which makes sense, since a ...
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1answer
34 views

Coaxial cable with electric flux

I had a question when I solved some examples of coaxial cables. I want to find the E and D field using $\rho_s = {Q \over {2\pi r L}}$. Here is my question: Why is the inner surface of the cylinder ...
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0answers
13 views

Potential energy of a shell & point system

Consider the system of a point particle with charge $q$ and a spherical shell with uniform charge $Q$ and radius $R$ whose center is a distance $r > R$ away from the point particle. I'm trying to ...
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1answer
49 views

Electric field at surface of a spherical shell

The shell theorem provides a well known result that for a spherical shell with uniformly distributed charge $Q$ and radius $R$, the electric field at a distance of $r$ from the center is: ...
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2answers
79 views

Electric Field from a Uniformly Charged Disk

As I was reading the solution of this problem the author gave the electric field in the point P as follows: $$ \vec{E} = \sigma /(2 \epsilon ) [1-x/(x^2+R^2)^{1/2}]\ \hat \imath$$ Where: $\sigma$ ...
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2answers
42 views

Relationship between work and energy in an electrostatic system

I am having problems understanding the relationship between the concepts of Work and Energy in a electrostatic system. As I know, the definition of Potential Energy is the ability to do work. In a ...
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2answers
65 views

If Electric field is constant in a region, does it imply potential is also constant?

I am a bit confused about these concepts- when is electric field or electric potential constant so i would appreciate if anyone could brief me about these things as well. Here i am referring to ...
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1answer
49 views

Gauss's law, electrical flux density [closed]

Q. Given a 60-μC point charge located at origin, find the total electrical flux passing through the plane z = 26 cm. I can understand what the question means, but I can't do anything. Is it using ...
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2answers
25 views

Is Emf induced in the coil when magnetic Flux passing through it is zero? If so then what is the explanation?

I thought Emf would not be induced if the coil doesn't cut the magnetic Flux . But since the graph in my paper shows Emf is induced when magnetic Flux is zero , I got confused. I thought since the ...
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0answers
26 views

When is force of interaction maximum?

A certain charge Q is divided at first into 2 parts q and (Q-q). Later on the charges are placed at a certain distance. If the force of interaction between the two charges is maximum then 1)Q/q = ...
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19 views

What does relative permitivity of medium mean and what does it depend on?

Does relative permitivity have someting to do with the polarization of medium , like for example how in inside the capacitor magnitude of electric field would be less due to a smaller opposing field ...
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1answer
20 views

Distribution of charge on isolated system?

An isolated solid metallic sphere is charged with +Q. What will be the distribution of their +Q charge on the sphere ? If it is conducting then the net charge resides on surface and if not the net ...
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2answers
38 views

Spherical Conducting Shells, Potential

When we have a spherical conducting shell and charge on outer surface of the shell then the potential inside remains constant i.e, kQ/R (R=radius). But say the inner surface of the shell is charged ...
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1answer
27 views

Things that must be considered when mass producing a capacitor [closed]

The question is to list four things that must be considered when a capacitor is chosen for inclusion in a circuit which is to be mass produced. Are there a specific set of four things? I've come up ...
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1answer
38 views

Coulomb's law and electric field intensity [closed]

here is question and solution I can't understand why R_x= 4a_z please explain it detail! ;-(
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0answers
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Please Can Anyone help Me to drive the equation for Electric Field Around a test Charge Around A uniform Ring. [closed]

Please can i get a mathematical relation for electric Field around a test Charge Lying in the region of influence around a uniformly Distributed Charged Ring .
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0answers
32 views

Self Energy (Classical Electrostatics)

In classical electrostatics, the total energy is given by $W_T=\frac{\varepsilon_0}{2}\int_{\mathcal{U}}{\left|E(\vec{r}')\right|^2 \mathrm d\tau'}$ , while the interaction term is $$W_I = ...
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0answers
17 views

the mathematical relation between dipole moment and frecquency

Is there any direct mathematical relationship between frequency and dipole moment and if so does it fit if there more than one electric field affect it?
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0answers
17 views

Time in Coulomb's law [duplicate]

If you have an electric charge somewhere and you make a new electric charge right now when do these electric charges start to interact with each other? is it immediately or it take some time ? how ...
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0answers
79 views

Mutual $E$ force due to charged coaxial rings [closed]

I found the following question in a good physics book I was solving and although this is a computer problem, I wonder if it can be done without using computers. $Q.$ Find the force of attraction ...
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2answers
16 views

Electric potential energy of a charge

Potential energy is the work done by the particle against a conservative force. Isn't it? when a charge is fixed on a free space and then when we bring another charge from infinity to a distance r ...
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0answers
44 views

Charged conducting wire ring and Greens function

ρ(r) = q 2πa2 δ(r − a)δ(cos θ). If this is my charge distribution on a conducting wire ring. radius=a. I am attempting to show my electrostatic potential as an integral along the z-axis I started by ...
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1answer
103 views

Basic concepts of electrostatics

How to deal with a grounded conducting sphere (I.e finding charge on it) in uniform electric field ? And if any two charged conducting spheres are in each other's electric field then will ones field ...
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0answers
21 views

Multipole expansion of the electric field generated by an infinite charged plane

Take an infinite plate with uniform charge density, the classical problem that is usually solved with Gauss' theorem, to get that the electric field outside the plane, at a point $\boldsymbol r$ is: ...
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1answer
30 views

Total potential energy in electric field?

if there are 2 charges generally potential energy of the system should be the sum of individual potential energy. but why the potential energy is half of the sum of every individual charge's potential ...
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0answers
36 views

Method of image charges — Why is a *grounded* plate needed?

In the classic image charge problem of a charge $q$ above an infinite grounded plane, it is well known that the field lines essentially behave as though there were a negative charge behind it, and the ...
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0answers
41 views

When deriving potential between plates of parallel plate capacitor, why isn't the charge distributed on the top *and* bottom of both plates?

Let's say we have a canonical parallel plate capacitor with area $A$ and separation $d$ where $A>> d^2$. A charge of $+Q$ is placed on the top plate and $-Q$ is placed on the bottom plate. We ...
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2answers
33 views

Electric field Intensity , parallel plates

My book says that the electric field due to infinite long plates doesn't depend on 'r', so does it mean that no work is done in moving a point charge towards or away from it? Also considering the ...
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0answers
12 views

coaxial capacitor potential calculation

How is capacitance of a cylindrical capacitor calculated? In his question his Equation 1 tells us how to calculate the potential of a cylindrical object and there are two locations where I cannot ...
0
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1answer
33 views

Does a conductor in an external electric field have a positive charge density and electric field inside?

I'm thoroughly confused by conductors. Let's say you have a round(ish), perfect conductor. Solid and uncharged. Some distance from it, we place a point charge $q$, giving rise to a field $\vec{E}$. ...
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1answer
27 views

Local charge density manipulation of ionized air

Assume we have ionized the air in an isolated container. Would is be possible to concentrate the ions within a specific region of the container with electric fields, i.e. to manipulate local charge ...
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3answers
80 views

Why charge is not a measure of inertia?

We know that mass is the measure of inertia of rest. Then why charge is not a measure of inertia? What causes the difference between charge and mass?
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1answer
18 views

About Electric potential

when we bring a unit positive charge from infinity to a point in the electric field EF does work on the charge and external work is also done on the charge in same amount but in opposite sign. then ...
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0answers
21 views

Null point (vector) between n point charges

I have derived the result for 2 positive charges, and for one positive one negative can be obtained by using the minus sign correctly. But I was unable to extend it or solve for n charges. Is my ...
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3answers
63 views

Electric Field Inside a Conductor at Different Charge Densities [closed]

We say that the magnitude of the electric field inside a conductor is zero, whether a hollow or solid. However, at certain charge densities, the magnitude of the electric field inside the conductor ...
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0answers
23 views

How does air density affect corona discharge?

I'm wondering how local air pressure and density affect the amount of ionizations occurring in a corona discharge. Also, does the threshold voltage required for a corona discharge vary with air ...